Processor: Core2Qaud Q9650 12mb Cache
Ram: 8gb DDR3 1333
HD: 1Tera WD
VGA: Nvidia GTX285 -1G - Point Of View
PS: Gigabyte 800W
Case: Gigabyte Sumo 5115
Monitor: HP W2248 24inch with HDMI Cable enabled by converter to the VGA Card
Keyboard Mouse: Logitech
Now I have to weird problem, my PC keep freezing a lot ... it always freeze when I play games like Call Of Duty 4 or any other games, and sometimes it freeze when I leave the PC Idle or watching a movie or even browsing ... just everything get freeze and a weird sound from the speakers and I have to make restart to work again ... did install many OS and still the same .. now I'm using windows 7 RTM 64bit
I would give a try on another usb mouse first like the user on that topic since you have one of the same brand, this can sound a little crazy but there are problems with some usb devices on gigabyte boards, maybe you can try to disable legacy usb on bios to see if it vanishes.
You said you installed some other OSes, what problem happened with them? complete freezes too or not complete freeze, same strange sound when it happens? Do you have any other usb device connected?
You can use Memtest86+ (http://www.memtest.org/#downiso) bootable cd to test your memory, but I am not sure if that is that case but if you want to be sure.. (FIY also hiren's boot cd, ultimate boot cd and Inquisitor have memtest86+)
BTW: the beast you assembled is way better performer than an iMac.. and is not ugly , hope it can be sorted out soon.