Computer wont start, no signs of life, power supply is good and green light turs off when plugging into computer

Hi there
Sounds like a common problem
when you plug the power pack into the laptop its power light goes off because there is a fault. Most commonly this is connected with the plug or the socket into which it goes or the motherboard.
visually inspect the socket, if the central pin is loose thats your problem, if not then check the plug/jack bend the cable on it as these are prone to breaking. wiggle it around whilst checking the power button and status lights if none of that works then you need to strip the laptop and perform a continuity test on the first stage.
ie between socket and motherboard. please note for any sign of exposed cable and remember electricity hurts on contact be carefull. especially if you test motherboard for voltage.
ps the switch is pretty reliable and i would not poke anything in that hole just yet.