Over the last week to 10 days I have had my system lock up on me on several occasions. The common denominator is that I amusing the browser every time this occurs.
If I am listening to music, as I usually am, the sound turns from whatever I am listening to to a machine gun type rat a tat - this often the first indication I get and then I notice that the mouse is immobile. When this happens I am not able to get the task manger by the usual Control Alt Delete, the only option is the reset button. If I attempt to recover the session I more often than not get another lock up.
My usual browser is Firefox, and when this happened twice just now I tried Google Chrome just to see if it was a Firefox specific issue, and the thing locked up again.
Recent changes to the system which could possibly be responsible are an increase in RAM, from 1 gb to 2gb, and installation of 1394 card. Both these changes happened around the beginning of the month so I has a good two weeks before the lock ups started, and am therefore reasonably confident that neither of these changes is responsible.
I also updated Firefox from 3.0.13 to 3.5.2 on the 7th of the month, once again nothing happened for a week or more.
I run scans for malware and viruses at least once a week and none of them has shown anything nasty for some time. Today I have scanned with Spybot and mbam, both were updated prior to the scans, and neither scan found anything wrong. I had an AV scan running (Avast) when the first of the lock ups occurred. Avast runs a memory test before you can run a full scan, which showed nothing, and the 1394 card now appears in the Network connections section of control panel, though apart from the motherboard it has never been connected to anything. I don't, and have no intention of, running my Internet connection via the 1394 card, until it appeared in the Network connections I had no idea you could run an Internet connection through firewire.
I am getting kind of annoyed at these lock ups which seem to be getting more frequent.
And I don't know what my next step should be. So ideas would be welcome.

Just had another lock up trying to access Wikipedia, I guess my curiosity about someone's phobias will have to wait for another day.
Also possibly relevant, I used both CCleaner and TFC to clear the caches and temporary directories earlier today so those are another couple of variables which can be eliminated.
Also, and just out of curiosity, how come thes apps find stuff in IE temporary folders when I never use it, apart from Windows updates?

The common denominator is that I amusing the browser every time this occurs.

And just how are you keeping them amused?

There are many reasons for sudden, unexpected lock ups. Certainly the new hardware is suspect and I would look at the RAM first. Pull the new RAM and see if it happens again. Your new RAM may not be playing well with the old RAM, or with this motherboard.

Heat can also be the cause. Watch your temperatures and make sure the interior is clean of heat trapping dust and dirt.

An underpowered or failing PSU can cause sudden lock ups. Did you ensure your old supply can handle the added demands of your additional hardware? Here's my canned text on testing supplies:

To properly and conclusively test a power supply unit (PSU), it must be tested under various realistic "loads" then analyzed for excessive ripple and other anomalies. This is done by a qualified technician using an oscilloscope or power analyzer - sophisticated (and expensive) electronic test equipment requiring special training to operate, and a basic knowledge of electronics theory to understand the results. Therefore, conclusively testing a power supply is done in properly equipped electronic repair facilities.

Fortunately, there are other options that are almost as good. I keep a FrozenCPU Ultimate PSU Tester in my tool bag when I am "in the field" and don't have a good spare power supply to swap in. While not a certain test, they are better than nothing. The advantage of this model is that it has an LCD readout of the voltage. With an actual voltage readout, you have a better chance of detecting a "failing" PSU, or one barely within specified ATX Form Factor Standard tolerances. Lesser models use LEDs to indicate the voltage is just within some "range". These are less informative, considerably cheaper, but still useful for detecting PSUs that have already "failed". Newegg has several testers to choose from. All these testers contain a "dummy load" to fool the PSU into thinking it is connected to a motherboard, and therefore allows the PSU to power on, if able, without being attached to a motherboard - great for testing fans, but again, it is not a true load or suitable for conclusive testing.

As mentioned, swapping in a known good supply is a tried and trued method of troubleshooting used for centuries, even by pros. Remove the "suspect" part and replace with a "known good" part and see if the problem goes away.

I do not recommend using a multimeter to test power supplies. To do it properly, that is, under a realistic load, the voltages on all the pins must be measured while the PSU is attached to the motherboard and the computer powered on. This requires poking (with some considerable force) two hard and sharp, highly conductive meter probes into the main power connector, deep in the heart of the computer. One tiny slip can destroy the motherboard, and everything plugged into it. It is not worth the risk considering most multimeters, like plug-in testers, do not measure, or reveal any unwanted and potentially disruptive AC components to the DC voltages.

And remember, anything that plugs into the wall can kill. Do not open the power supply's case unless you are a qualified electronics technician. There are NO user serviceable parts inside a power supply.

As for your temp folders, other programs use IE's temp folders too, including add-ons.

Also...

Please download VEW and save it to your Desktop: http://images.malwareremoval.com/vino/VEW.exe

Double-click VEW.exe then under Select log to query, select:
Application
System

Under Select type to list, select:
Critical (Vista only)
Error

Click the radio button for Number of events
Type 20 in the 1 to 20 box
Then click the Run button.
Notepad will open with the output log.

In Notepad, click Edit > Select all then Edit > Copy
Reply to this post, click in the reply window and press Ctrl+V on your keyboard to paste the log.

You could also have a resource conflict with the card or it could be bad. Are you sure that it works? You've never tested anything in it? Only change one thing at a time on your system. I wouldn't try to add any new hardware until we have this figured out but I agree to try and remove the new ram first. One more thing, have you recently installed any new updates?

Well thanks to all of you for prompt and helpful responses.
Digerati, Okay I goofed in my punctuation, and the space bar is so large.
As for the other issues it sounds like it is off to the shop for this one. I once restored a motorcycle and constructed the wiring harness myself. 12 volt no worries, even if you get on the high voltage side of the coil it will only give you a "thrill." Which is not pleasant, but not life thretening either.
Anything that plugs into the wall is the territory of professionals.
Question:
Would said professional also be able to run tests that would, for lack of a better word, "push" the new RAM cards and see if they have any faults? Checking that the PSU could cope with extra RAM is not an issue that occurred to me, I was confused enough making sure that the RAM was compatible with the motherboard, so it seems possible that may be an issue.

Townsbg:
The RAM came from a reliable source, and I had no issues for a couple of weeks, so as I said I am reasonably confident they are okay.
When installed, due to poor short term memory I installed the RAM, restarted the computer and checked system properties which showed I now had 2gb of RAM. I then did some other stuff on the computer. It was later that day that I remembered the 1394 card, so technically I did only change one thing at a time.
As for updates I have received Windows updates including updates for IE 8, in the period of time since the changes to RAM. I also had an update to Silverlight, which surprised me as I thought I had declined the original offer of Silverlight. It doesn't do anything that I am likely to need, but there it was in Add/Remove so I downloaded the update.
The other main change that occured around the same time was replacing Symantec Corporate AV with Avast as the former had become unstable. I think that gets a mention in the log below.

Broni, here is a VEW log:
Vino's Event Viewer v01c run on Windows XP in English
Report run at 29/08/2009 9:44:58 AM

Note: All dates below are in the format dd/mm/yyyy

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'Application' Log - error Type
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Log: 'Application' Date/Time: 28/08/2009 2:57:44 PM
Type: error Category: 1
Event: 2 Source: ACW_DE
Abnormal termination by the user.


Log: 'Application' Date/Time: 21/08/2009 3:32:52 PM
Type: error Category: 0
Event: 2004 Source: PerfNet
Unable to open the Server service. Server performance data will not be returned. Error code returned is in data DWORD 0.

Log: 'Application' Date/Time: 21/08/2009 3:32:52 PM
Type: error Category: 0
Event: 2004 Source: PerfNet
Unable to open the Server service. Server performance data will not be returned. Error code returned is in data DWORD 0.

Log: 'Application' Date/Time: 18/08/2009 10:30:40 PM
Type: error Category: 0
Event: 2004 Source: PerfNet
Unable to open the Server service. Server performance data will not be returned. Error code returned is in data DWORD 0.

Log: 'Application' Date/Time: 18/08/2009 10:30:40 PM
Type: error Category: 0
Event: 2004 Source: PerfNet
Unable to open the Server service. Server performance data will not be returned. Error code returned is in data DWORD 0.

Log: 'Application' Date/Time: 18/08/2009 10:08:30 PM
Type: error Category: 0
Event: 2004 Source: PerfNet
Unable to open the Server service. Server performance data will not be returned. Error code returned is in data DWORD 0.

Log: 'Application' Date/Time: 18/08/2009 10:08:30 PM
Type: error Category: 0
Event: 2004 Source: PerfNet
Unable to open the Server service. Server performance data will not be returned. Error code returned is in data DWORD 0.

Log: 'Application' Date/Time: 18/08/2009 9:49:33 PM
Type: error Category: 0
Event: 2004 Source: PerfNet
Unable to open the Server service. Server performance data will not be returned. Error code returned is in data DWORD 0.

Log: 'Application' Date/Time: 18/08/2009 9:49:33 PM
Type: error Category: 0
Event: 2004 Source: PerfNet
Unable to open the Server service. Server performance data will not be returned. Error code returned is in data DWORD 0.

Log: 'Application' Date/Time: 16/08/2009 5:37:37 PM
Type: error Category: 101
Event: 1002 Source: Application Hang
Hanging application SDFiles.exe, version 1.6.1.7, hang module hungapp, version 0.0.0.0, hang address 0x00000000.

Log: 'Application' Date/Time: 16/08/2009 5:36:48 PM
Type: error Category: 101
Event: 1002 Source: Application Hang
Hanging application SDFiles.exe, version 1.6.1.7, hang module hungapp, version 0.0.0.0, hang address 0x00000000.

Log: 'Application' Date/Time: 08/08/2009 11:54:47 PM
Type: error Category: 101
Event: 1002 Source: Application Hang
Hanging application firefox.exe, version 1.9.1.3497, hang module hungapp, version 0.0.0.0, hang address 0x00000000.

Log: 'Application' Date/Time: 08/08/2009 11:54:23 PM
Type: error Category: 101
Event: 1002 Source: Application Hang
Hanging application firefox.exe, version 1.9.1.3497, hang module hungapp, version 0.0.0.0, hang address 0x00000000.

Log: 'Application' Date/Time: 08/08/2009 11:54:05 PM
Type: error Category: 101
Event: 1002 Source: Application Hang
Hanging application firefox.exe, version 1.9.1.3497, hang module hungapp, version 0.0.0.0, hang address 0x00000000.

Log: 'Application' Date/Time: 30/07/2009 11:49:30 PM
Type: error Category: 0
Event: 51 Source: Symantec AntiVirus
The event description cannot be found.

Log: 'Application' Date/Time: 30/07/2009 11:49:30 PM
Type: error Category: 0
Event: 5 Source: Symantec AntiVirus
The event description cannot be found.

Log: 'Application' Date/Time: 30/07/2009 11:49:29 PM
Type: error Category: 0
Event: 46 Source: Symantec AntiVirus
The event description cannot be found.

Log: 'Application' Date/Time: 30/07/2009 11:48:19 PM
Type: error Category: 0
Event: 51 Source: Symantec AntiVirus
The event description cannot be found.

Log: 'Application' Date/Time: 30/07/2009 11:48:17 PM
Type: error Category: 0
Event: 5 Source: Symantec AntiVirus
The event description cannot be found.

Log: 'Application' Date/Time: 30/07/2009 11:48:16 PM
Type: error Category: 0
Event: 46 Source: Symantec AntiVirus
The event description cannot be found.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'System' Log - error Type
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Log: 'System' Date/Time: 21/08/2009 3:32:29 PM
Type: error Category: 0
Event: 1002 Source: Dhcp
The IP address lease 169.254.249.111 for the Network Card with network address 0016E66F4A68 has been denied by the DHCP server 192.168.1.254 (The DHCP Server sent a DHCPNACK message).

Log: 'System' Date/Time: 21/08/2009 3:16:53 PM
Type: error Category: 0
Event: 4307 Source: NetBT
Initialization failed because the transport refused to open initial Addresses.

Log: 'System' Date/Time: 21/08/2009 3:16:47 PM
Type: error Category: 0
Event: 4307 Source: NetBT
Initialization failed because the transport refused to open initial Addresses.

Log: 'System' Date/Time: 18/08/2009 12:59:25 PM
Type: error Category: 0
Event: 7022 Source: Service Control Manager
The Windows Time service hung on starting.

Log: 'System' Date/Time: 16/08/2009 5:46:49 PM
Type: error Category: 0
Event: 7000 Source: Service Control Manager
The bcftdi service failed to start due to the following error: Insufficient system resources exist to complete the requested service.

Log: 'System' Date/Time: 16/08/2009 5:46:49 PM
Type: error Category: 0
Event: 7000 Source: Service Control Manager
The bc_filter service failed to start due to the following error: Insufficient system resources exist to complete the requested service.

I will await Broni's interpretation of the log before I do anything to the box, though I do agree going back to the old RAM will isolate that as a source of the problem. One fly in that ointment is that even if I leave the new RAM in, which I will for the time being, it could be days before there is a repeat of the problem. (If it turns out that the new RAM is the problem, or part of it, I will be more than a little cheesed off. I have never run short of RAM, well I have never had any mesages from the sytem saying it is low on virtual memory. The extra gb was really future proofing.) When it comes to electrics/electronics the worst faults are intermittent ones.

After looking at the log a couple of other events come to mind, which may be relevant or helpful. My password is stored inside the modem. I followed the instructions on the ISP website to change password, but then had to phone them and go through the process again as the new password was not accepted. And there was another occasion where I was unable to get on to the net. With the assistance of my ISP I made some changes to the settings of my modem which sorted that one out.
I await.

If you look at errors log, you can see, the last error (applic., and system) occured on 8/21/09, a week ago.
Does it mean, you didn't have any problems over last 7 days?

Hi Broni,
I cannot account for why that log shows no problems in the last week.
It happened three times in quick succession yesterday, and again after my first post, hence the second post.
Looking at the Event Viewer I see 2 errors in Applications @2.58pm locally yesterday, which was about the time I was having these problems.
Details Source: ACW_DE, Category: Devices, Event: 2

The next error shown in Event Viewer is indeed the 21st August but I am certain I have had problems between the 21st and yesterday. The previous evening I gave a ride home to the IT person from where I work, and I was picking his brains about the problem. It was in the front of my mind as it had happened more recently than a week ago. Pretty sure that it had happened if not earlier that day, then on the previous day.
Why this does not appear in the VEW log I can't explain but I have certainly had problems in the last seven days.
See attachment.
Event Viewer is not a part of Windows I am really familiar with, I know that in the past I have had things happen that have appeared in Event Viewer and others that didn't. Why? I don't know.

My first suspect would be Norton.

Try this....

Go Start>Run (Start Search in Vista), type in:
msconfig
Click OK (hit Enter in Vista).

Click on Startup tab.
Click Disable all
IMPORTANT! In case of laptop, make sure, you do NOT disable any keyboard, or touchpad entries.

Click Services tab.
Put checkmark in Hide all Microsoft services
Click Disable all.

Click OK.
Restart computer in Normal Mode.

NOTE. If you use different firewall, than Windows firewall, turn Windows firewall on, just for this test, since your regular firewall won't be running.
If you use Windows firewall, you're fine.

Same problem?

Regardless of the source the ram could be defective (even though it initially worked) or not even match with your old ram (which would also cause a problem) & it is still suspect until proven otherwise why is why I (as well as bill; initially his suggestion really) suggested to try and take the new out. If you still have your problems after taking it out then it is probably eliminated as the problem. As for testing one thing at a time, I was referring primarily to your troubleshooting. I might also suggest silverlight as that is a browser add on. Have you tried uninstalling and reinstalling FF? The norton suggestion is good as it has been known to cause problems.

As for the PSU it is more than a "thrill" as it can kill you!!! You have been warned!!! Only experts that are well protected should mess with it. End of story.