All my 3 fans are working BUT my PC's power button doesn't light up and, I have checked on the cables/fans/motherboard everything seems fine though as I press on the power button nothing comes up as it usually is green the desktop is blank WHAT SHOULD I DO!?

Remember to post the details you would want to know if you were going to work on your PC. You have 3 fans and a PC. That's not going to help must. Try tell the rest of the story like "It worked fine until I installed a new __!"

I was cleaning my fan and when I put it back into the PC it made a high noise then stopped working altogether though my fans are still working.

Sorry if I was too subtle. Finish telling about this PC, make, model, and why is this fan needed at all? Why did you clean it? Overheating much?

Yeah the PC was overheating it's a pavilion hp. It had shutdown repeatedly after a 10 min period because of the dust it was gathering.

I take it you won't reveal further details. At this point treat it like the dead PC and strip it down to basics, replace the usual heatsink compounds, the CMOS battery and see if it comes back. All that work is on youtubes and more. If this is your first foray into PC repair, then let's hope you have a wing man.