Hello, My computer won't start up anymore. I press the run button and one of the lights up and the fan starts but nothing else turns on and the monitor doesn't register that the tower is turned on nothing smells like it's been fried or anything does anyone know any possible reason for this?

This usually means a bad power supply in my experience. The computer will turn on and the POST will attempt if it were something else.

Make sure the monitor is plugged in, if your hearing beeps look up your computers beep codes they can usually help you.