Hello to all. I am having a serious problem with my hardware. I have spent more than week googling for the problem and found nothing exact... The problem is - my PC crashes with every game I play for now. Monitor turns black and tells that ""entering sleep mode" - but the sound sometimes keeps playing the games soundtrack for a while… But sometimes lags for a few seconds and disappears. The only way to get PC back to work is, hold power button until it shuts off and then turn it on again. I did not have any problems at all - was a happy gamer - with no problem... Played all versions of Crysis with no problems... Fallout 3 - no problems.. Assassins Creed, All versions of Prince of Persia, i even can't remember - but really much games without any problems.. And now i am being punished Anno 1404 - sometimes it crashes after 30 minutes of gaming - sometimes just after loagind... Godfather 2 - crashes after 3 - 4 min of game play Batman Arkham Asylum - have run it twice - first time crashes in elevator with Joker… Second time at first battles 2'nd round... And the crash is always the same as describet before. For now have not tested more games... My system is: Chieftec 650W C2D E8400 2 x 8800GT SLI (enabled it with help from this forum ) MB: GA-P35-DS4 4 x 1 GB branded RAM What has been done? First of all this is nothing to do with temperatures... because PC runs in Nine Hundred Case.. all fans on Max... + CPU has an Arctic Cooling on it and GPU has ZALAMAN on it - none of temperatures get above 50 degrees. This is not VGA - because I got another new one - and it did not solve - so I run them SLI now I think that this is not a OS thing... because same happens in XP... same in Vista... 32 and 64 bits.. now running Win 7.. 32 bits... still same happens... This is not a bios... flashed it to the latest from Gigabyte site (F14) This is not a driver.. Video Runs on latest driver from Nvidia... I am not sure about RAM... i have not tested it with tests.. i just took 2 modules form friend and run these games... same crashes happened. Maybe PSU is dead - but I have no idea how to test it... Red some forum about Realtek onboard sound that it could cause the problem.. tried to install driver from Realtek - not MB site.. still the same... have not tried run games with sound disabled - don't know how to disable it - nothing is shown in BIOS... will it work when disable it under Device Manager? So - I know you have great experience - please if any of you has a clue what could be the reason or what else could i do - please tell me. Hope to hear from you! P.S. Sorry if the post is not in the right category.