Diverse Blåskärmar, kan det vara hårdvarufel?

Anyway, my problem is with my fathers computer that I built in October last year:

Intel Core i5 750 2.66Ghz
4GB Corsair XMS3 1600MHz RAM
2x Samsung Spinpoint F3 500GB
AMD Radeon HD 4650 512MB
Gigabyte P55 UD2 (mATX)
Corsair VX 450W

with windows Vista x64.

He used his computer a lot for video editing as well as writing and surfing. I had the CPU clocked to about 3Ghz and the memory to 1500Mhz(from 1333 because of the mobo underclocking the RAM).
So what happened was that I was trying to check the CPU temps because the Sony Vegas editing program seemed a bit unstable while rendering( I thought I might try to reset the clock frequency or check that the CPU wasn't getting to hot), so I opened a program from Gigabyte called Easy Tune 6 and all of a sudden while I was clicking around the program the computer froze and when I restarted I couldn't get in to Windows, it would just pop a BSOD and reboot sometime during OS load. It was possible to get into Safe mode sometimes, but often it would crash before I got there. And when I tried to use windows in safe mode, it was pretty unstable. From Safe Mode I tried a system restore but without success, and I also tried getting into the recovery console with recovery vista DVD, but it would be Blue screen before I got into the recovery program.

So I thought, damn Vista, I'm gonna buy my father Windows 7 and format the C partition since there's pretty much only programs and the OS itself on it. But as it turned out I could not use the vista dvd, the win7 dvd or a Xp cd to get in to some kind of recovery console to format the drive. Just Blue screens and crashes. This is when I thought there might be some kind of hardware fault on top of the OS not working properly. But I plugged in the HDD into my sisters computer and formatted the C partition, plugged it back in to my fathers and when I tried to install Windows on it I got the blu screen as usual while the DVD was trying to load. And this is without an OS even installed?! So I figured that windows must be crashing due to it encountering some kind of faulty hardware like the RAM or VGA RAM etc. What I've tried so far is taking out the RAM sticks on at a time and also switching places- there are two of them - but to no avail. Although one of them seems to be working better than the other, but that might just be coinsidence.
Another problem is that the BSODs I have been getting are a lot of the time not the same, I've probably seen around 5-8 different. But here's a list of them:

The first error message I saw after the first crash was something about a missing or corrupt ntfs.sys. (Which I tried to replace from safe mode but couldn't)

Others:
0x00000070

After format of C: IRQL_NOT_LESS_OR_EQUAL 0x0000000A

With one RAM stick:
0xc0000021 missing or corrupt file ntoskrnl.exe;
0x00000050 PAGE_FAULT_IN_NONBE_PAGE_AREA and also ntfs.sys error;
volmgr.sys missing or corrupt and 0xc0000098;

With one RAM stick and only C drive:

SYSTEM_SERVICE_EXCEPTION 0x0000003B fbwf.sys

There might also be some others but I can't remember which ones.

So what do you guys think? What seems to be the problem?

Thanks,
/Snorkelfarsan