PC Freezing completely with no error message

Hi, my PC has been frequently freezing for a while now and everything I've tried has not worked - the system simply freezes, the screen does not change, none of the fans turn off, and I get no error messages, the PC does not time out into a blue screen. I have to hold down the power button to turn it off, so the only error I get is the Kernel 41 event (63).

This may have corresponded to me getting a new graphics card however I have downgraded to my old one and the freezes are still happening.

I have tried -
Different HDD's(taking out my secondary)
Changing graphics cards
Changing and swapping RAM
Downgrading and upgrading graphics drivers
Disabling and uninstalling sound drivers
Formatting with fresh drivers
Unplugging and re-plugging all the inside component wires

I think it may be a PSU issue however I want to be sure before I spend a fair amount of money. Could it also be a faulty ssd or motherboard, perhaps I should try a bios update. I'm thinking more and more it could be the ssd even though it is only about a month old.

All temps are fine and I've never had any problems with load
I have searched for a few days now about this issue and it is extremely hard to find anything without any obvious error codes available

PC specs are

ASUS P9 X79 Pro
W7 64bit
i7-3820 @ 3.6ghz
20gb RAM (only using 16)
ATI Sapphire Toxic R9 270x 2gb
120gb SSD
1.5tb HDD

If anyone has any input that would be greatly appreciated.

Code:

Version	6.1.7600 Build 7600

Install Service Pack 1 via Windows update, it is an important security package that when left uninstalled could result in serious security issues.

We could enable Driver Verifier to see if a driver is causing the freezing.

Enable driver verifier but only enable the options: Standard settings and IRP logging step 3.
Don't enable Force Pending I/O Requests

Enable Driver Verifier to monitor the drivers.
Driver Verifier -Enable and Disable
Run Driver Verifier for 24 hours or the occurrence of the next crash, whichever is earlier.

   Information

We use Driver Verifier as it puts a stress on the drivers, and so it makes the unstable drivers crash. This should flag the driver responsible in the dump file.
It

Driver Verifier will make the system laggy, this is normal so don't worry.

Before enabling DV, make sure that you have earlier System restore points made in your computer.

If there are no points, make a System Restore Point Manually

Post back the results.

Been away for a few days so haven't been able to use my PC since then. But now that I can I have ran the verifier as per instructions and enabled the mini-dump on windows, I can now induce a crash by launching Rome:total war II. However it is just a straight freeze and will not produce any crash files, i'm not even sure the verifier is running after restart, how can you tell?

Thanks.

Another fresh format this time, only using 1 RAM slot and removing the SSD. Again random hard freeze with no errors this time when watching a youtube video. I am now contemplating buying a new motherboard or PSU, as these are the only things I can imagine are causing the issue, would anyone know any way which I can narrow down the cause, to save me money if I make the wrong guess?

Before my most recent format I had updated windows as far as it wanted to go, and am doing so again as we speak. I've ran the Diagnostic tool both ways and there are no dumps. I'm pretty sure I have it up correctly. How do I get a dump from a hard hang scenario? Will the PC eventually turn off and dump or will it run for as long as it has power?

These are my current settings

So I thought I fixed it - I had found by looking through all the bios options that the DRAM slots were all abnormal, so I removed all the RAM and only used the ones that reported as 'OK'. after this (whether or not this was the fix is unknown as the pc is now crashing again) it seemed to be going strong. So getting cocky I plug in my SSD and all my other RAM checking that they reported back OK in bios. and did a fresh format. However now lo and behold the crashes are back.
This time however with a BSOD. This should be more helpful.

BCCode: 1000007e
BCP1: FFFFFFFFC0000005
BCP2: FFFFF8801016FDBB
BCP3: FFFFF88004067328
BCP4: FFFFF88004066B90
OS Version: 6_1_7600
Service Pack: 0_0
Product: 256_1