Hi, I've just built a new pc but I have a problem with it's stability. While just running Windows it seems to be ok, but when I play games (Mainly happens on F.E.A.R & Doom 3 [Half Life 2 seems stable for some reason]) my system will either freeze and I have to press the reset button, or it will just restart the system itself (No blue screen or anything). This can happen either as soon as I start the game (On the menu) or after 5mins or 50mins of play. I don't think it's an overheating issue as my CPU temp is 40-50 degrees, my system is about 40 degrees and my GPU is about 50 degrees. No component has been overclocked and I'm using the stock drivers that came on the CD's with the parts. My system is listed below: AMD 64bit X2 4200+ (AM2) 1GB (2x512) Crucial Ballistix Dual Channel DDR800 PC2-6400 (4-4-4-12) Asus M2N-E Seagate Barracuda 7200 250GB SATA-II 16MB HIS ATI Radeon X1900 XT ICEQ 3 SILENT Heatpipe 512MB GDDR3 Pioneer DVR-111BK 16x16 DVD±RW Dual Layer ReWriter Antec Sonata II Piano Black Quiet Case - 450W Smart Power PSU (Running Windows XP Pro SP2) Please if anybody can think of anything that might be causing this problem I would really like to know as I've just spent a lot of money on it and for it not to be stable is really really annoying and I don't know what to do, I don't have any spare components at the moment to try and switch parts to see if I can determine if anything is faultly, but I doubt there is anyway. Thanks in advance if anybody replies, Callum.