Whole windows 7 system randomly locks up, requires hard reset

[auroraborealis]

Below are the specifications of the system:
OS and Hardware:
Windows 7 Home Premium 64-bit
Cooler Master 650w PSU
MSI 760GM-Ps23 (FX) + AMD 760G + SB710 Micro ATX AMD Motherboard
AMD-FX 4300 Vishera 3800 GHz - Set to 3.8 GHz
2GB - 4GB Kingston HyperX DDR3
NVIDIA GeForce GT 240 ASUS
SeaGATE 465GB HDD 7200 RPM
LG internal Super Multi Drive SATA GH24N580
Gigabyte GZ-F3HEB

Drivers:
NVIDIA 3D Vision Controller 335.21
NVIDIA 3D Vision Driver 335.23
NVIDIA Graphics Driver 335.23
NVIDIA HD Audio Driver 1.3.30.1
NVIDIA PhysX System Software 9.13.1.1220
NVIDIA Virtual Audio 1.2.20
Realtek Ethernet Controller Driver

Software: The only software installed to the system is Steam, League of Legends, Path of Exile, FireFox and Skype (Latest Vers)

Issue: The machine appears to randomly and completely seize up at times, no windows error logs are produced, neither are any windows mini dumps. The entire system becomes unresponsive and requires a hard reset to resume.

 

[auroraborealis]

Cooler Master 650w PSU

Which one is it exactly?
Is it new?
How many pc's has that graphics card been in? Are they of the same age?

It's the Cooler Master GX650W http://www.coolermaster.com/powersupply/gx-series/gx-650w/

It's less than a year old, built manually.

The graphics card has been in at least two PCs, however little is known about the previous one, I can only assume that because this PC is a relatively new build, the other PC was considerably older.

 

[auroraborealis]

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