I don't know if I would bother too much in trying to diagnose the fault. Your machine should be returned to the reseller under any Warranty and get them to fix or replace it.
To get further information about the error look in your Event viewer.
Look in the System or Application folder. You can get to the Event Viewer via right click My Computer icon and select Manage.
Any errors logged in the Event Viewer can be expanded by double clicking on the error line.
Take any event error I.D. number and search for it on these sites.
To check your RAM.
To check your Hard Drive.
The drive manufacturer will have free diagnostic software to check your drive for problems.
You can also load the Recovery Console and run ChkDsk /r to check for problems.
HOW TO: Install and Use the Recovery Console for Windows XP (Q307654)
To check your drivers.
HOW TO: Verify Unsigned Device Drivers in Windows XP
To check conflicting software.
310353 - How to Perform a Clean Boot in Windows XP
316434 - HOW TO: Perform Advanced Clean-Boot Troubleshooting in Windows XP
310560 - How to Troubleshoot By Using the Msconfig Utility in Windows XP
Removing adware & spyware
faq608-4650
Will check your computer for spyware and adware.
To checkout unnecessary services you are running.
See if you have any services that are flagging as "Starting" but not actually running.
Some general things to try.
See if System Restore will get you back to a restore point before your problem with Windows.
Try Safe Mode (Do you have this problem in Safe Mode?).
Try running ChkDsk to check your drive for errors. Right click your Drive icon/ Properties/ Tools/ Error Checking.
Run the System File Checker program from the Run Box by typing.....Sfc /Scannow in it and have your XP CD handy.
If they don't work you could try repairing windows itself by running it over itself. You will lose all your windows updates but your files will be untouched.
How to Perform an In-Place Upgrade (Reinstallation) of Windows XP (Q315341)