I've been having issues with my computer freezing. No BSOD. Just locks up completely. After i do a hard reboot. It usually freezes again on repair. Sometimes it won't. If I can log into safe mode and do a system restore it will work again for a few hours to a few weeks.
I tried loading ubuntu on a usb drive, but it loads the menu and won't let me select an option. The ubuntu install works on my wife's laptop.
It took out my video card and tried the onboard, no change in the problem. I've run memtest and microsofts memory test and both said the ram was good.
Here is my current set up. My computer is about 4 months old.
I'm running Windows 7 Ultimate 64bit
AMD Phenom II x4 965
ASUS M4A89GTD PRO/USB3 - AM3 - AMD 890GX
Antec EarthWatts EA650 650W Power Supply
Sapphire Radeon HD 6850
Samsung 1 TB Spinpoint 7200 RPM 32MB Cache SATA 3.5
XIGMATEK BALDER SD1283 120mm Long Life CPU Cooler
Kingston HyperX 8GB (4 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600
Sounds like something is shorting. Did you check to make sure all the connectors are plugged in? I would guess the problem lies with the mobo/cpu if it won't load from USB drive and memtest came back ok. Did you check to make sure nothing metal is touching your mobo? what kind of case do you have?