Mysterious issue with Pavilion G6-1021sv (weird crashes & BSODS, no apparent reason)

I own a Pavilion G6 that I've been using for a little over a year without problems - at least until a week ago.

One day, while browsing the net, Windows gave me a ton of errors simultaneously (every program I had been using at the time crashed with an error message) and then I got a BSOD.

After the laptop shut down, I could not turn it back on - I pressed on, the fans came on, the power led came on, but no POST.

The Caps Lock light was blinking in intervals of 3 - this apparently signifies a memory module problem. However, swapping the memory modules with another pair (tested to be working) did nothing.

I finally managed to bring the laptop back to life by disconnecting and reconnecting the CMOS battery thus performing a CMOS reset.

I then proceeded to flash the latest official bios (version F.65).

Everything was going well, until, you guessed it, I started receiving mysterious crashes in Windows and random BSODs again.

Analyzing the BSOD minidumps proved fruitless - each time, a different driver was apparently the culprit. Most of the time though, its either ntfs.sys or ntoskrnl.exe which obviously points to something hardware related. Also, sometimes, instead of BSODs I would get various errors (like stack overflows in Internet Explorer), or Aero/various services/explorer.exe crashes etc. Each time, I get a 'Windows must now restart because XXXXX service has been terminated' and the laptop restarts.

The laptop passes every HP diagnostic and quite a few hours of memtest86. It even passes stress tests like Linx, without problems. It does not overheat. I have also swapped the HDD with another one, just to see
if this caused the problem - it didn't.

My question is: what could possible be the cause of these mysterious crashes?

I tried formatting the HDD and installing a fresh version of Windows 7, but the crashes are still there, even before installing any of the drivers...


Thanks in advance!