Hi everyone. Sorry to be a nuisance. My Windows 7 Home Premium desktop PC has been functioning fine until recently, but now I'm experiencing sudden shutdowns. There's no BSOD, just a suddenly dead PC.
Restarting in Safe Mode is fine but nothing in the Event Logs helps because there's no opportunity for event reporting with a shutdown. Instead, all I see is "The previous system shutdown at such-and-such-a-time on such-and-such-a-date was unexpected". Well, uh, yeah. It sure was.
SFC reports 100% verification with no errors and, therefore, no fixes. Malwarebytes Premium reports no infection. The PC's hard disk health is good and has 4% fragmentation, which is OK with me. Its separate SSD, on which Windows is installed, is also working correctly. (I have two drives so as to keep Data separate from System.)
Computer shutdown occurs regardless of the program in use at the time. I could be browsing the 'Net with nothing else running and then: gone. Or using Microsoft Word, and then: gone. Or doing some editing in Photoshop. . . and then: gone. There's no warning of any problem anywhere. Computer re-start from Safe Mode is perfect as is shutting down or re-starting from Safe Mode. And then, when things seem to be back to normal, shutting down from fully loaded Windows, and opening fully loaded Windows, is no problem at all: boot-up time is 22 seconds; I can't grumble about that.
As for the PC during actual operation, it's quick, trouble-free and (hitherto) been utterly dependable, even if now 5 years old. Spec is: Windows 7 Home Premium 64-bit SP1 / AMD FX-4100 / 8GB RAM / Asustek motherboard / 1279MB Nvidia GeForce GTX 570 / Crucial SSD 238GB / Western Digital 931GB HDD.
To sum up, then: there seems to be no identifiable problem here with Windows itself or the programs and apps on this computer. If anyone can think of any explanation for what's happening, or any advice as to what I should / could be doing diagnostically, that'd be appreciated: thanks!