After Pc Case dropped about 3 feet fails to power-up

While servicing my desktop I inadvertently let the case drop a distance of about 2 feet. Now when I attempt to power it up nothing happens - no fan spin-up , only one little led light illuminates on the m/b.

I realise that to remedy this situation will involve a process of illimination and to get me started on this I would be grateful if anyone could reply to 2 questions I have initially.

1. Is it possible to trouble shoot the performance of the m/b here or , at least , illiminate m/b damage from the cause of the PC failure to boot here?

2. Is it also possible similarly to isolate the existence of any damage to the power supply?

I've now got everything working again. First thing I discovered was the reason for the completely dead PC. I didn't mention this in my OP but my problems started when I damaged my original graphics card by snapping off the externally protruding DVI/VGA adapter . I then attempted to replace this with an identical card which caused lots of problems as this card like the original , was too big for my case - fitting it into the slot was extremly difficult and this one also got damaged but the strugling to plug it into the m/b displaced the little power connection without my noticing this - hence the "dead " PC ! once I pluged this back in I got normal spin-up of all the fans but still no graphics. I was now convinced the problem was a damaged m/b but , after replacing the 2nd card with a physically smaller one , I got everything back to normal again.