Computer randomly crashing.

[Energize]

Running Windows 7 here, my pc has been fine for months but in the last few days it has been crashing fairly frequently in different ways, sometimes applications like games will crash to desktop, sometimes I get a bsod saying uncorrectable hardware error, a couple of times the display has just been garbage with the pc making a buzzing noise and then shutting off. And sometimes the pc just freezes and I can't do anything, even the restart button doesn't work!

Can't figure out where to start really, tried putting cpu back to stock but that didn't makes a difference.

 

[Energize]

Thanks guys, I'll do memtest in a min. Don't know if it's significant but when I tried to load a certain area in skyrim it kept crashing, but after I restarted it loaded normally.

 

[Energize]

Ran memtest86 for 5 passes and 0 errors.

There were two WHEA warnings.

A corrected hardware error has occurred.

Reported by component: Processor Core
Error Source: Corrected Machine Check
Error Type: Internal parity error
Processor ID:

A corrected hardware error has occurred.

Reported by component: Processor Core
Error Source: Machine Check Exception
Error Type: Internal parity error
Processor ID: 0

Those warnings tally like this.

Installation Date = 10/07

15/08
26/08
01/09
03/09
04/09 2
09/09
13/09
25/09
05/11
14/11
07/12
19/12
22/12
27/12 2
30/12
01/01 2
07/01 2
12/01
14/01
16/01 2
17/01 2
18/01 16
19/01 3
20/01 29
21/01 117
22/01 88
24/01 11
25/01 3