All my processors show up in device manager as working properly however they don't show up in task manager nor in resource monitor and I can see from my cpu usage that they arn't running. I just got my powersupply replaced and did a lot of windows updates. This is very confusing
What OS are you using , ?? Because in some BIOS there is a place where you can check or uncheck that puts the CPU at a MIN. State like only one core?? Go into the BIOS set to load defaults , than reset any custom settings you have made and reboot.