You may have filled in your system spec's, but we can't see them, I've heard that has had problems lately. So we don't even know what mother board you have, etc. We really need to know what we are working with.
The paper clip test is only a semi-valid way to test a PSU. Sure it may start, but can it provide all the voltages and current needed to run the board, etc. PSU problems can cause strange things with PCs. What PSU are you using?
So the PC was running in the past it seems, correct? For how long?
It seems now you are getting no signal to the monitor, correct? It might simply be the video card is bad, if you use one, but then we don't know...