Yesterday morning I turned off my PC. I forgot to take my flash stick out, so I tried disconnecting it properly, but did not have enough time and the PC shutdown normally. When I tried turning it on nothing turned on. No beeps, noise, smoke, smell. I opened it up and not one fan moves. What could be the problem here?

I'M REALLY stressing out here. My finals are next week and I have some major projects in my computer. Noooo lol.

I got a new PSU and plugged it in, and my computer still will not start. This is my second time installing a PSU, so if there is any advice I appreciate it. Is there a way to test the PSU itself?

There are a couple of ways to test a PSU, the safest one being buy an ATX psu tester, the not as safe method would be to 'jump start' the power supply with a paper clip or wire (google it, I really don't wanna be responsible for anything nasty, just incase).

Make sure everything is connected up properly and if it STILL doesn't work you may be looking at a bad motherboard, smoke and smell seem to suggest blown capacitors, check the motherboard over, there will be battery like things, they should be perfectly flat on top and not buldging, they should also not be leaky, if they are, the chances are the board is dead.

Below is an example of blown capacitors, see how the top is buldging and they're leaky?

I had to go somewhere, but when I came back the the main power connector was not in right, so I pushed it in. It's working now. Maybe I should try this with my old psu as well. Thanks Lebowski for the advice. Other then the paper clip method, I'll use your advice for future problems

I would back up all your work as well, just in case.