My computer keeps rebooting after it reaches the desktop screen. It's an 2.2 amd quad, radeon hd3870 512mb card, gigabet mobo, os is xp, 2 gig ram. I just got the new hd 3870 yesterday because the old one fried and it worked fine all last night, until this morning. After turning the computer on it would reach the desktop and keep rebooting over and over and over, you get it. It works fine in safe mode. Should I try to reinstall the drivers, do a system restore, or just go ahead an REFORMAT. I dont have anything important on the harddrive that I need at the moment. If anyone has any other trouble shooting techniques or questions please ask.It could be a heat issue...have you removed a side panel to see if any housekeeping is in order ?No, I definately don't think it's a heat issue, I would say the temp in there is well below the maximum parameters set. The computer was off all night and when I tried starting it is when the problem started. It's booting from sitting all night. All fans work.The machine was working fine until you installed the HD 3870? You are talking about this video card?

http://www.techspot.com/review/76-asus-radeon-hd-3870/




Yep, THATS the card, but it worked for a full day before I got this problem this morning.Test the card in another machine...

You may also be underpowered...Clik Here...I have a 700w power supply, so I know for sure that I'm not underpowered. Can't test on another machine because this card is PCI-E and my old dinosaur is only AGP. I have XP SP2, fully updated, everything is updated, no viruses, no spyware, no adware, its pretty much a clean computer.I would suggest you boot into safe mode and uninstall your video drivers. After do a reboot normally and than reinstall them.

Yeah, that's KIND of what I figured I had to do. I'll give that a try, this will be the second time I've installed these drives from the CD it came with, if this doesn't work them I'm probably just going to go ahead and start from fresh.Unfortunately the only real way to determine if the card is the issue is to swap it into another machine...perhaps someone you know has a PCI E system ? ?I agree with patio...more so that you done this 2 times. This is very telling in itself.

I know, it's kinda wierd. But what are the odds of getting 2 deffective video cards. I WISH I knew someone with a PCI-E slot because that would have been my first stop.Another thought. The DVI input from my monitor is connected to my HD 3870 video card. If it was the card and I was in safe mode with no problems what so ever wouldn't it still display the same type of problem while not in safe mode seeing as it still attached to the video card. My mobo VGA card is turned off.I did a system restore on my computer to the day that it was working which was last night and low and behold the computer is working perfectly. So whatever I did last night before bed was bad and shall never be done again, I really wish I knew what it was. Thanks a lot for all of your suggestions, lots of big brainy people here (jealous). PeaceGood to hear your persistence paid off...feel free to stop by anytime.
And Welcome to CH !