Running WinXP on the machine, it's only about 2 years old, the video card work fine (tested it in my other computer), the hard drive sounds like it is booting up, ram is in the correct place and works in other computers, no beeps from the mobo when it's starting up. When I hit the power button, the computer sounds like it does when it used to work but the monitor is black and doesn't recognize the comp (if that makes any sense).

Any help on this would be excellent. Thanks everyone.

you tested the video in the other computer did you test the monitor on the othere computer ,also a weak power supply could cause this ,also try disconecting the keyboard and mouse ,and boot computer