Laser Computer Lock Combination Reset Help! What's Wrong With My Computer?

Help! What's wrong with my computer? - laser computer lock combination reset

I have my own built-in computer with a new Gateway monitor, and the chairmen of course keyboard and mouse. Much has been done so far. He turned around and I was using, and the mouse stops working. The light in mice (red laser), the always on, when the computer is turned on, it was deleted. Then the screen went black. She still had the power because the power button. I turned the computer on and off several times, unplugged all the cables and plug everything back - nothing helped. If the monitor is turned on, the message "No Signal", just before it goes off again. The keyboard is odd, so ... When you turn the "No". Lock 'light is lit, and immediately deleted. At other times, which now moves more to turn on or off. All these elements worked perfectly until today, suddenly. What could solve the problem? "No adoption at a price that is the problem? ( about $ 50 or $ 500?)