I've found that often times the obvious cause and effect doesn't turn out to be true (i.e. your brother).
Do you have Divx installed? There is a problem with older versions of Divx and XP SP2's Data Execution Prevention (DEP). You would need to update your Divx for that fix.
You can do that by choosing "Safe Mode with Networking" so you can log on to the net in safe mode and download it. (This problem causes crashes in explorer.exe and folders with thumbnail views activated)
You can also do three other quick things:
First, if you can, open My Computer. Right-click on your hard drive(s) icon(s).
Left-click Properties. Left-click Tools. Left-click "Check Now". Left-click "Automaticallyh fix file system errors". Left-click Start (don't click Scan for and attempt.."
If this is your Windows hard drive, a message will come up telling you "The disk check could not be performed...blah blah". It will ask you if you want to schedule the disk check to occur the next time you restart the computer. Click Yes.
Do this for each hard drive. Other drives may check successfully immediately, as they are not locked by windows. But reboot for the Windows drive to be checked.
Now, once you've completed that step for your drives, do this:
Put your XP CD in your CDROM drive, preferably the same drive you installed it with.
Exit out of the installation screen that comes up.
Click your Start Button. Click Run. In the "Open" box, type (without quotation marks):
"sfc /scannow"
Note there is a space between sfc and /scannow.
Click OK.
A rectangular box will come up called the System File Checker utility. It will scan all your system files to make sure they are correct and not corruted or wrong versions. Not to worry because it does take into account any hotfixes or service packs (so it's not going to put an old system file from the CD on your system when it knows there is a newer copy from a service pack on your drive!)
It will finish and disappear after awhile. If it keeps saying to put your CD in, it just means your cdrom was not the path Windows was originally installed from. In that event, you have to keep clicking "Retry", and it will continue. You may have to click Retry a number of times if this occurs. But it will eventually finish.
Reboot afterwards.
Also, your pagefile might be corrupted from the shutdown. It's worth it to make sure it's a fresh pagefile to avoid having errors. Here's the easiest way to reset it.
1. Click Start.
2. Right-click My Computer.
3. Click Properties.
4. On the Advanced tab, in the Performance section, click Settings.
5. In the Virtual Memory section, click Change.
6. For Paging file size for selected drive, click No Paging File, and then click Set.
7. Click Yes IF the following warning appears (the warning might not appear):
If the paging file on volume X: has an initial size of less than xx megabytes, then the system may not be able to create a debugging information file if a STOP error occurs. Continue anyway?
(X is the drive letter and xx is the amount of RAM installed on your computer minus 1 megabyte.)
8. Click System Managed Size.
9. Click OK four times, and then restart the computer when you are prompted