| When I had the same problem I narrowed it down to memory, it turned out to be overclocked memory causing constant restarts downclocking it slightly resolved the issue.
I have also recently fixed somones computer which again was narrwoed down to memory causing the problem however it turned out it was a faulty 1GB stick causing random freezes.
What I'm saying is most porblems are with the memory but specifiaclally is hard to say what it is.
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My System: xX_TeK_GaMeR_Xx Processor(s): Intel Core 2 Duo E6700 | Motherboard: GIGABYTE GA-EP45-UD3P | RAM Memory: OCZ 6400 2 x 2GB ReaperX | Graphics Card(s): MSI NX8800GT | Sound Card: Realtek ALC 889A Dolby Digital | Hard Drive(s): OCZ SSD 60GB, WD 250GB HDD | Optical Drive(s): LG HL-DT-ST DVDRAM GH22LS30 | Case / PSU: Cooler Master HAF-932, OCZ 600W | Cooling: Stock | Network / Internet: Ethernet, BT @ 2mb (250KB/S DL) | Monitor(s): Xerox XA7-17i, SHARP LC26D44 | Operating System(s): Windows 7 Ultimate RC1 X32 | |