computer won't boot after upgrading cpu in Troubleshooting Posted November 13, 2018 I have an asrock h97m pro4 mobo and tried upgrading my CPU to an intel i7 4790k. When I tried to start up the computer nothing showed on the monitor, the case fans didn't start spinning. The CPU cooler did work and I could hear the hard drive spinning. I switched back to the old cpu and the computer booted just fine. I updated the bios and cleared the cmos, then switched the CPU back to the i7 and still no luck. When I tried to boot it up the CPU fan and hdd started up but nothing showed on the screen.Any and all help appreciated. Sorry if this sounds confusing I'm kinda an idiot.