I have a few year old HP computer with Windows 2000 Professional on it, whenever i turn it on it loads up all the way until the desktop comes up and then shuts off and reboots itself....anybody know how i can fix that please!!

ThanksSee if it will let you boot to "safemode"....after you reboot...watch for the loading screen to tell you to hit F8 for more options & do so...then PICK safemode...if it then boots in safe....go to "Start/run/...& type in the following....sfc /scannow, & hit enter. There is a SPACE between sfc & / or it won't come up. have your 2000 disk handy to insert as it will tell you to do this. This checks the file SYSTEM for errors & if thats the problem it will rewrite the files from the disk. I have this come up occasionally...I just scan & REPAIR.
If this doesn't do the trick...then boot from your CD..& use the repair option....if this doesn't work...let me know...I'm an old hand with 2000!!Is there anyway to do it without the 2000 disc???Well...the MS site tells ya it will work off the files already in the system...but if those are the "corrupt" files then it won't.....So yes you do need the disk...can you get into safemode?? If so & you don't have a disk...then run a virus scan from there & see if that cures anything.
Yes i can get into safe mode, i will try the virus scan and see what happens...Ok...run a spyware & all too if you have it....if it's lettin ya into safe then it's not hopeless.
If you can boot to Safe Mode, your video card may be a suspect. Do you have separate video card, or on-board one?It won't run without the CD...