At the weekend I installed a new PSU, reformatted one of my drives and installed a new dvd drive since then my computer locks up playing games Sometimes I can play for hours, sometimes 10 - 15 minutes. Sometimes it just freezes and I have to manually reboot Sometimes it freezes with a high pitched scream and I have to reboot and tonight it just rebooted on its own Theres nothing in the system log, and no minidump. The system failure settings are set to write an event to system log, send and administrative alert and dont automatically restart but it seems to have just done the exact opposite. My GPU temp is 41c and all my drivers are up to date. I dont know what to do with it. It happens with the Sims and with World of Warcraft - I havent tried any others. It happens when I'm tabbed out of game just browsing and when I'm in game.