As the title suggests, my computer has been restarting randomly and without warning. Before I go on, here are my system specs, according to the D-A-L Hardware Scan. I left out a few fields that I considered irrelevant.

--Computer System
* Manufacturer: Gateway
* Model: T5042

--Motherboard

* Manufacturer:
* Model: RC410-SB450 (v )

---Processors

1. Intel(R) Pentium(R) 4 CPU 2.93GHz (GenuineIntel)
* Max clock speed: 2.93 GHz
* Socket: Socket 775
* Version: Model 4, Stepping 9

--Video Devices

1. ATI RADEON XPRESS 200 Series
* Resolution: 1280 x 1024
* Colour Depth: 32 Bits
* Refresh Rate: 75 Hz

--Operating System

Microsoft® Windows Vista™ Home Premium ()
* Version: 6.0.6000
* Build Number: 6000
* Install Date: 24/10/2009
* Install Directory: C:\Windows
* Locale: English (en) - Canada (CA)
* DirectX version: DirectX 10

--Bios

* Manufacturer: Phoenix Technologies, LTD
* Model: 6.00 PG
* Release Date: 17/01/2006

Memory

* Total Current Physical Memory: 0.37 GB
* Total Current Virtual Memory: 0.85 GB
* Maximum Memory Capacity: 1.00 GB
* Memory Devices:
1. Type: SDRAM* - Speed: MHz - Capacity: 0.50 GB



Anyway, the problem started around ~5 months ago, for no apparent reason. I haven't been able to determine a cause, except this: Whenever playing any game or running any application that uses 3D rendering, my computer ALWAYS crashes a few minutes in. Over some time, I've also collected the following information:

* 3D applications/games aside, I can run my computer somewhat fine, but it still crashes sometimes. About once or twice per day is normal.
* Before I had Vista, I was using XP, and the restarts were still present.
* I've reformatted my hard disk several times, to no effect.
* My computer will still crash in Safe Mode, although it happens less frequently.
* There is no BSOD when my computer restarts, even with "Automatically restart" disabled in the system options.
* After checking my Event Log, I found "Error 6008: The system shutdown at <date> was unexpected." I've provided the binary data for the event below:

Code:

In Words

0000: 000B07D9 00090001 000B0010 034F0027 
0008: 000B07D9 000A0002 000B0000 034F0027 
0010: 00000960 0000003C 00000001 00000960 
0018: 00000000 000004B0 00000001 00000000 


In Bytes

0000: D9 07 0B 00 01 00 09 00   Ù.......
0008: 10 00 0B 00 27 00 4F 03   ....'.O.
0010: D9 07 0B 00 02 00 0A 00   Ù.......
0018: 00 00 0B 00 27 00 4F 03   ....'.O.
0020: 60 09 00 00 3C 00 00 00   `...<...
0028: 01 00 00 00 60 09 00 00   ....`...
0030: 00 00 00 00 B0 04 00 00   ....°...
0038: 01 00 00 00 00 00 00 00   ........

That's about all the information I could find. If you need any more, then ask me and I'll post up whatever I find.

3 suspect areas: bad RAM, failing power supply, heat. Below are my canned texts on RAM and PSU testing. For heat, you need to check your temps, and of course, make sure your system is clean of heat trapping dust, and that you have plenty of front to back air flow. You might try opening the side and blasting a desk fan in there.

You can test RAM using one of the following programs. Both require you to create and boot to a bootable floppy disk or CD to run the diagnostics. Using the floppy method is generally easier (and another reason to include floppy drives in new builds). However, the CD method is just as effective at detecting RAM problems. Allow the diagnostics to run for several passes or even overnight. You should have no reported errors.

Windows Memory Diagnostic - see the easy to follow instructions under Quick Start Information.
or
MemTest86+ (for more advanced users) - an excellent how-to guide is available here.

Alternatively, you could install a single RAM module and try running with that to see if it fails. Repeat process with remaining modules, hopefully identifying the bad stick through a process of elimination.

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.

Originally Posted by Digerati

MemTest86+ (for more advanced users) - an excellent how-to guide is available here.

I thought you might want to know that that guide cannot be found. I was wanting to read it.

Hmm, it seems they moved it. It can now be found here. Thanks.