I put together a brand new PC. Turned out pretty good except the PC randomly locks up and freezes. I can make this happen by scanning the HD with MS Security Essentials, but it also happens at other times. I have to do a hard boot to get running again. You may have seen my other recent thread that stated the monitor was randomly going blank. That was not true, the power setting was set to turn the monitor off at 30 minutes. What was happening was the PC was locking up just like now except the monitor was already off (power setting). The power setting is now set to never turn the monitor off and the PC still locks up. The build goes as follows: AMD Phenom II X4 955 processor, Gigabyte GA-MA785GMT-UD2H MOB, 2 4 Gig Mushkin 1333 MHz DDR3 memory, Window 7 Ultimate, 500 watt PS, Nvidia GeForce 7300 video card, (I need to upgrade), and a WD 1TB Caviar Black HD. All of the drivers are up to date, cpu never gets above 54C, normally around 48C. The BIOS is set to load fail safe defaults.