I have run memtest and dskchk in dos to verify RAM and HDD integrity because I was getting lots of pc lock-ups where the only thing to do was hard shutdown.
The two most recent errors i got was driver_irql_not_equal_or_less with stop: 0x000000C4
the other page_fault_in_nonpagedarea with win32k.sys error, no stop code.
Have done the steps in the sticky.
Former minidumps were accidentally deleted when I ran a disk cleanup.