I posted in another thread too.
I used to have this problem as well, especially during gaming. I searched for a long time for solutions, everything points to RAM problems. I was suspecting it could be faulty RAM. Luckily that didnt seem to be the case. After some experimenting, it turned out to be underpowered RAM.
Some solutions online suggest that this is due to underpowered power supply. But it could be much simpler than that. At least for me I know for certain the PSU was good.
The way I fixed it was going to BIOS and change the voltage setting for the RAM. As it was, the settings before were indeed underpowered by the RAM's specs on the website.
After increasing it to the voltage level to spec, I have not experience those random BSoD's telling me IRQL less than or Equal to. This lasted for many months now (it used to be quite frequent) and still worked fine until my current computer troubles, which probably has nothing to do with ram.
Since different motherboards have different BIOS interface and diff RAM have diff specs, I cannot specify exactly what you should change it to or how; or if this even applies to you, though the symptoms are similar to what I endured back then. That said, perhaps you might want to give it a try and see if it helps? (also, ask the great people here to help if you dont know how to properly configure BIOS. I researched extensively when I did it, and still there were unexpected issues that prevented me from even booting. It was quite scary, so you should definitely get help if you don't know for sure to save some headaches.
If you want to try this, I'd suggest specifying your exact RAM model, check its official website for its specs for voltage (or ask people here..?)
The brand of mobo so people here can know what your BIOS look like, to better guide you through the process.
I hope you resolve this annoying problem; It took me 2 years on and off to finally get rid of it. I hope you don't need to.
EDIT: By the way, I ran memtest back then, and instead of failing, it just froze; tried it many times and it just freezes. Even bad ram should fail, but my situation was so bleak it just froze. But the problem turned out to be much frightening and was relatively easy to solve.
Edited by xenoss, 01 October 2009 - 06:35 AM.