In general, IRQL_NOT_LESS_OR_EQUAL indicates that a kernel-mode process or driver attempted to access a memory address to which it did not have permission to access. The most common cause of this error is an incorrect or corrupted pointer that references an incorrect location in memory.
In many cases, it is hardware issues which might be caused by a device driver VGA , Sound
i just recently fixed that problem in my desktop. it was a virus that got past my avast suite. i used Safe Returner virus removal program to get rid of it. it was a relitively new [mAloB] virus. i havent gotten the bsod irql screen since then.