Random BSOD (Physical memory dump)

Hi, I am reliably informed that this is where a problem can be sorted. I will try and break down what i have done. Because I tried everything to narrow down this problem.
Firstly my System is now 6 months old, and i built it my self, as follows.

Antec 900 case
OS = Vista Home Premium 64bit
Intel Duo Core 3.16 ghz with Mugen Infinity cooler
Gigabyte GA EP45C DS3
XFX Nvidia GX 260 Black Edition
X2 (4Gig) Corsair CM2X2048-8500C5D XMS2 5-5-5-15 Ver 1.1
Corsair TX 650Watt psu
1 DVD RW
onboard sound

This pc ran absolutely error free, not even a hang up for six months. till just 1 week ago, and i gradually started to get the odd BSOD and now i get it often. I did from new, update bios, and also make sure i have the latest drivers. I ran cpuz and stats were good. The memory voltage in bios is set at the required 2.1 operating voltage.
I also tested the memory, as i have read most BSOD are generally memory orientated, they passed fine, no errors. I also read that the virtual memory can cuase such issues, this is also set correctly ( anyway, ran for 6 months without issue).
I did try some new memory, exactly the same as above only difference on close inspection is the memory is ( Ver 2.2 ). Funny thing was though, this memory although slightly updated version would not work in my system would hang on boot up. So put original memory back and works fine.

I also done a complete format of my single 1TB HDD, re-installed vista, I had only installed AVG Security 8.5 after format, and as was updating got BSOD again. I persisted and ALL day put all my software back and all windows updates, during this time i did not get one problem, ran fine. In the evening, tried some online gaming and for 2 hours NO problem, then for no reason what so ever BSOD again. At the moment it is fine, but i am at a lost to track down the culprit, my system is basic with nothing not needed, but good hardware, highish spec.

Any idea's, most appreciated. Thank You

Thank you for that, I have done as you said and unchecked it, so i will be able to get the error next time it happens. When it doe's I will post the error. Thank You again for helping.