I've been getting a series of system freezes (black screen, clock on my Logitech gaming keyboard freezing for ~20s before the system resets) and BSODs for about 5 and a half months. Looking through the Event Viewer the first seems to have been 19th Jan 2012 while the latest was today. There seems to be no pattern to when they happen - some as soon as the Windows desktop loads, others after the PC has been on and running fine for hours. Most of the time I get freezes but from time to time I get the blue screens with errors such as 0x4e, 0x19, 0xA, 0xC2 and 0x24. Various internet searches have told me it could be hardware-related (particularly memory) or something to do with the registry. I did install two new memory sticks (the Corsair ones) around the 15th Jan (4 days before the first crash) and I seem to remember the system crashing during a programme install at around the same time. Looking through the Event Viewer shows each crash (84 to date) is marked by "Critical 07/06/2012 18:07:51 Kernel-Power Event ID:41 Task Category63)" with a total of 17 different BugcheckCodes of which 78 is the most common, followed by 26. I've attached all the SF Diagnostics, CPU-Z and RAMMon readouts in the following zip file: View attachment MrCheeseUK-Seven Forums.zip Any help would be most appreciated, thanks EDIT - forgot to say that I've tried the Windows chkdsk and memory diagnostic and both came back clean (though the system crashed when Windows had booted right after the most recent memory diagnostic).