Well XP has a very short temper and the simplest error would give you the BSOD. Things you could try...
1.Run a system clean up; start, all pro, accessories, system tools, cleanup
2.Run a the defragmenter; same place, but disk defragmenter
3.Run the check disk utility; the quickest way to get there is; start run; then type "cmd" to open the command prompt then type "chkdsk /r" and press enter, it might say it cant lock drive and ask if you want to run at next restart, press y for yes then type exit to close the comprompt and then restart the computer. this would check your hard-drive for bad sectors ect. and recover lost information in possible which may be the cause.
4. The problem may be caused by a cluttered registry and lost & empty keys. The best way to clean it up is with a registry cleaner. There are many free cleaners on the market a good one is "ncleaner" can be found at "www.nkprods.com" You can also purchase "RegCure", "www.regcure.com"
5. The system just may simply overheat, when running graphic intensive games. Try cleaning the inside of dust; have a new fan installed;