Pc not booting after cpu replacement

[BlazeTortoise]

Hey guy I recently replaced my intel i3 8100 cpu with an i5 9600k and my pc is not booting up. After I plugged all of the external cables back into the pc i turned it on, the leds on the fans lit up and every fan in the system started. This was usual, but then then the keyboard and mouse did not turn on(an indicator light is present) and the monitor showed only a black screen. My mobo (msi 7370 a pro) has a few indicating error lights that light up whenever  something is wrong, i see nothing. If any of you can help I would appreciate it.

[Bazrat]

Did you update the BIOS beforehand? I know sometimes you would have to update the BIOS if going forward a generation or something along those lines. If not you may have to put your 8100 back in, update it and put the 9600k back in afterwards.