Computer issues. Black screen BSOD 116 etc

[Aliadra]

So, about a week ago my computer decided that it would be a good idea to randomly black screen while I was playing.
When I restarted it started just fine, until I launched said game again, whereas I got another black screen. The third time I rebooted I barely got into Windows before it blackscreened.
This is still going on. If I try to boot it I (sometimes) manage to get into windows, maybe click a thing or two until it blackscreens, then it happens sooner and sooner. Even while in BIOS until it reaches a point where the VGA_LED on my motherboard is lit when trying to boot. (Managed to get a BSOD 116 once)

So now I am using the computer's fans as cooling for my laptop and accessing files on the desktop.
But today I saw that DRAM_LED was on when I was checking what was going on (As it didn't boot into OS)
I tried swapping the RAM sticks back and forth, and after one slot working, I couldn't get that slot working, but then another slot worked (Two do not work at all)

Everything is back to stock clocks. CPU was OCed and GPU was flashed with 6970 BIOS.
Blackscreens happen at any time (Except when loading windows or in BIOS it's just lots of colours) and it happens when trying to boot from the W7 DVD.

setup:
Intel i5 2500k
Sapphire Radeon HD 6950 stock
Asus P8P67 Pro
2x4 GB Corsair Vengeance
Corsair HX 650

Any input would be lovely.

[Biernot]

BSOD 116: GPU fried, faulty vga driver or a failure with the connection CPU <-> GPU ***

A faulty GPU is the most likely cause, but as you seem to have also problems with RAM it could also be CPU or motherboard.
The only way to diagnose this problem is to swap out parts until you found the faulty one. Borrowing a VGA (doesn't matter if the same model, just needs PCIe interface) or some RAM from another computer is easy. CPU would require a bit more effort.


*** The connection CPU <-> GPU consists of the following steps:
1. Video Card
2. PCIe slot on the motherboard
3. PCIe interface in CPU (in older generations this was part of the mb northbridge)
4. CPU