Help my pc has fallen and it cant get up

[ghostrdr]

A few days ago my picture on the modem started to get dastorted.Well i thought it was the vid card.I am in a dusty area so i thought cleaning it might be a good idea.Well i cleaned it and put it back together.It worked for a few days than did it again.I cleaned it again and it worked for a minute than the screen got distorted,than it shut off on its own.Now i took it apart cleaned it and put it togther again.Well i have a wireless mouse and keyboard(logitech).When the pc is off the led indicating the keyboard and mouse are working is on when i turn the pc on the led turns off.In order for my modem to work i need the keyboard to work so that i can insert the modem to the pc.Also i do not hear the pc booting up only the power turns on and nothing else as if nothing is working except the power supply.Any suggestions would be appriciated before i pronounce the pc is dead and give it the proper burial.