I have an AMD FX8350 processor on a Gigabyte GA-990FXA-UD3 motherboard. Windows 8.1. My PC shuts down on its own. It worked fine for over 2 years until I had to replace the processor. Any thoughts as to why it shuts down? Microsoft tech team ran tests on all hardware several times and could not find any problems. They also checked for viruses.
This started happening after my original processor died. The first replacement did not work and the 2nd processor is working but my PC just shuts down on its own at different times. Of course it never shut down while in the repair shop. They checked for over heating, which it didn't. I have tried to notice if there were any particular things I was doing before it shuts down. Sometimes it shuts down while I am working on it and sometimes it shuts down when I am away from it. It has even shut down when I had nothing open.
It might be that your power supply isn't good enough for your new cpu, or you have a faulty motherboard.
What was your old cpu and did you overclock it? And how exactly did the old cpu die?
Also posting your complete pc specs would help a lot.