Well all need help deciding on new card!

Hello all

Need help deciding on new graphics card for my system. Specs dual xeon 3 ghz processors, intel MB S5000XVN, 4 gig Kingston ram, OS windows 7 64 bit, 1kw power supply, 8800 gtx (at this time).

Here in lays the problem I have since eArly march 2011 had random wArm reboots! Have ran every known hardwAre test taken to local computer shop. And nothing ever fails or comes up bad. Even had electrician look at outlet junction box and fuse box no problems either. This only occurs when gaming. I mainly play WOT, Starcraft II, company of heroes is the main 3. This problem may not happen for weeks then it may do it three times in a week or 3 times in one night. But only when gaming. Have had some sAy that since my MB is a server board that could be a issue. The system has been running since 2007 with no issues till now. Have posted on here before and got lots of good ideas but nothing is helped. Another source says the 8800gtx has had issues with crashes and freezes?

So at point where I want to try a new video card. Nothing to extreme but something better than the 8800gtx I have. With the mb s5000xvn intel what do you all suggest. WAs leaning with 9800 series force??

Sorry for misspells or English doing this on iPhone not use to keypad! Thanks all in advance!

Fullmetal2011