CPU upgrade nightmare

[Joe.Bailey1]

Hi, I recently got a i5 8400 from a g4560 when I installed it my pc wouldn't turn on, so I reinstalled the g4560 and it does turn on but now I get no hdmi signal from my GTX 970 or integrated graphics. I'm kind of stressing out so any help would be appreciated. I now realise I need a new mobo for i5 but my usb ports have no power now and i have no hdmi signal from device even though overall nothing has changed and i have triple checked all sockets. One other minor point is that my graphics card hdmi slot is just to the left and the case hole is a little too right for it to fit in easily but this wasn't a problem as I used the pc for about a year and a half prior to attempting to upgrade my cpu. The first time I installed i5 and then back to g4560 i didn't touch anything to do with gpu.

[LukeSavenije]

tried to just simply clear the cmos?