Hello, I have a home built computer that my wife is using. It will go into sleep mode out of the blue. The only way to restart is turn the power off or hold the power button down for a few seconds. It will then but to the start Windows normally and work fine. No patern that I can figure out. The computer has been in working fine for 3 months from when I built it. It is running W7 64 bit, 6GB ram, 750W power supply. I have checked the power settings and made sure nothing was on. Ran scans for virus and malware. Any ideas on what would cause this problem? I am trying to avoid changing the power supply and trying different ram if I can. Any help would be nice. Thanks.