If your computer is not turning on, there are a few things you can quickly try that will get it running again in a few minutes without having to dish out cash for repairs.
The obvious one is to check the power cable, make sure there is power to the system, that the power strip and power supply are turned on.
However folks often miss the simple ideas of trying it in another socket, or directly plugged into the wall.
One other trick people hardly ever know is to remove the power cord, and hold in the power button for 15 to 20 seconds, and try turning it on a few times still disconnected. This discharges any remaining voltages in the system, and lets it start from a fresh power configuration.