How to identify the cause when nothing happens after switch on

[dlresponse]

Ive tested the PSU which is fine. So either Ryzen 3 3200g cpu or the
Gigabyte A320M-S2H board. 16 gb ddr4 ram is a third option.

No signs of life at all on switch on and there is no speaker to cause fault beeps. The PC was incredibly dusty which has probably the cause

 

[dlresponse]

Yes all the obvious stuff has been checked for. Apparently it just failed during the evening a few nights ago. I an trying to see if there is a sneaky way of dianosing cpu / board without beeps or another machine to swap parts. PSU IS FINE

Can lots of dust kill a machine like this? It was pretty severe