I have a Win7 x64 on a HP 625 laptop. I've reinstalled Windows twice or thrice because of other problems, but this issue keeps popping up: Mostly when gaming, but completely randomly, Windows goes to sleep. It's not a temperature issue because it won't ever pass 75 degrees Celsius. I noticed that it won't happen that often with a fresh install of Windows, but after a while things tend to go downhill. Is this a update aka software or a hardware issue? I've found this in my eventmanager: The system is entering sleep. Sleep Reason: Button or Lid. I assure you that I didn't do any of those things.
Something must be broken about your laptop lid. ACPI sensors on the lid can go out of whack. Also, another culprit is low battery life. Try checking your power settings in Windows 7's control panel. By the way, I know that Windows' condition becomes worse every day (my WINDOWS folder is more than 23 gigs!), so see if you can optimize your 7 or try another OS.