OK, so are you suggesting the best thing to do is reinstall XP?

How do I go through my services one at a time? Uncheck one service at a time from the MSCONFIG utility?

If you are looking for the fastest fix then a reinstall would work. There are many questions & ideas as you navigate the Dell site. Follow the steps from this page:

http://support.dell.com/support/topi...G&l=en&s=dhs#0

If you want to try troubleshooting the System Services:

Do not use msconfig to disable services. Type in the Run box "services.msc" instead!
Before disabling ANY service, check out the information listed about each service by clicking on the name.
Only disable a few services at a time to avoid changing "50" settings and trying to figure out "what broke it."
Still unsure? Put your setting to "manual" or the listing under "Safe." Manual allows Windows XP to start the service when it needs to (or when ever it feels like it,) but not at boot up. NOTE: Depending on your configuration, not all services will start when required while in Manual mode. If you find you need a service, place it in Auto.
After adjusting your service settings, reboot your computer.
If you do not have some of these services listed, don't panic! If your computer manufacture "pre-installed" your XP, they choose not to have certain services installed for you.

http://majorgeeks.com/page.php?id=12

Also: look in your Event viewer: rt. click My Computer then click Manage then Event Viewer.
Or: Administrative Tools/Event Viewer or Start/Run/ eventvwr
Open the system as well as the application tabs & look for X errors. Click error line for details.
Post back the source & event id especially of errors that seem to coincide with a crash.

OK, I think I have narrowed it down.
The problem lies with Norton Internet Security.
When I go to Internet Security Options, uncheck 'Show Norton Internet Security icon in the System Tray (Recommended), set it to start up manually (as opposed to when the system starts), and then restart, the computer works better. It loads up quicker, and I can use system restore.

Furthermore, when searching through your link to the Dell Solution Network, I found a tool called 'Crash Analysis Tool'. It told me that these two files 'may require a driver or application update'....

tfsnifs.sys - Sonic Solutions
SYMTDI.SYS - Symantec Corporation

I looked for the SYMTDI.SYS file, but haven't found a new version. Do you think it's this that's causing Norton Internet Security to slow down my comp and stop System Restore from working?

Norton is very invasive software in the sence that it alters Operating Systems extensively.

What version of Norton's Security are you using? Anti-Virus too?

The issue with the System Restore could also be tied to Norton's Protected Recyling Bin (which I've always found superfluous & troublesome).

Do you have the XP SP2 firewall disabled? You should only run one firewall.

symtdi.sys shoud be located in the folder C:\Windows\System32\drivers.

Some malware can camouflage themselves as symtdi.sys particularly if they are located elsewhere.

Yes, I'm starting to regret paying my subscription for this now, it seems to be the source of all my troubles!!

I don't particularly just want to use the Windows Firewall though (which is currently disabled).

Again, I'm pretty sure I don't have malware, as I have done extensive testing in the HijackThis Section.

I want to try reinstalling Norton Internet Security, but I have to pay to get a CD, as it came pre-installed on the computer - Thanks, Symantec!!

Any suggestions as to what I should do?

Are things working as they should without NIS? Are you still running Norton Anti-Virus?

If you are looking for an alternative firewall here is a good review page.

http://www.firewallguide.com/software.htm

I've used Outpost Free for many years & am very satisfied with it. If you have multiple computers & or run your business on the computer you probably want to invest in a full paid version.

http://www.agnitum.com/products/outpostfree/index.php