Question PC turns on but doesn't give off HDMI signal to monitor and doesn't connect to keyboard and mouse either

[Khepri711]

My PC has recently stopped sending am HDMI signal and doesn't turn on my keyboard or mouse. Everything seems to be running fine in the computer just from a quick scan inside and still runs but it doesn't give off a signal or turn on anything. I suspect that the motherboard would be the culprit as both the graphics card isn't giving a signal and all usb ports are not working but I still want to hear another opinion. I have tried removing the battery from the motherboard and replacing it with a new one which worked for about a day before it went back to doing this. The GPU fans are still spinning and everything still seems to be working just no signals whatsoever.

 

[kurdtnz]

Please list full system specs, cpu, gpu, motherboard, psu etc.