Computer acting strange

[tat327]

So, I have had this pc for about 3 years. Its not that pretty and is pretty much bottlenecked everywhere. But it was still running fine even then. Today, Its been freezing a lot, and then suddenly, it just stopped working! It turns on, but wont display. The monitor is fine but the usb ports on the back also dont seem to functional either. The lights on my keyboard flicker sometimes so its getting a connection. The only thing its doing right now is not displaying, not making my keyboard and mouse turn on (So it seems.) I have re-seated everything, still nothing. I swapped out the processor, still nothing. Fans run and everything. I really need this computer to work because I cant currently afford a new one. It would also blue screen a good number of times before it started freezing. I can promise there is no Malware. I do scans weekly (Malwarebytes). Please help!!

 

[Phazoner]

Seems like the motherboard or most likely the PSU has died.