Uh oh! Why my computer beep twice when I press the power button, but don't turn on?

Two Beeps. Parity error

http://www.computerhope.com/issues/ch000607.htm

Good Luck

That is normal IF the computer has sound. If it doesnt have sound but it has sound at the begining like some computers is k . BUT IF it doesnt have any sound at all then is a problem so try turning off the volume or checking if your computer has a starting music adjustment.

AND ERNIE B is wrong that website doesn't help you at all!

Unplug your computer, and open your case and ground your self. Take out the all RAM sticks and put them back again. Or go to your BIOS and in the Boot order choose hard drive as number 1. Tell me if this helped so I can find out on future similar situations.