When I start my PC the cpu isn't turning on. It is giving power supply to mouse and keyboard but its not turning on. No led of cpu is turning on or glowing. The fan is not running. What could be the problem. Please help . Can it be repaired

I would say that the motherboard is bad. I have had the same thing happen with an Asus motherboard. The board gets a short in it somewhere and will also burn up the power supply. You can try one thing first and if that does no good you need a new motherboard: Take out battery on motherboard for 20 minutes and then replace. If it will then boot up and fans will run it's okay. If not, turn off quickly to keep from burning up power supply. Smell the power supply and see if it smells like it's burning or has burned. If so, replace it, too.