Computer wont boot up properly, urgent plz

Hello,

I boot my PC up and find a big red line down the middle of my screen, read up about it onlien and get told that i may have a faulty/broken video cable, so i jig my video cables around a bit and now it doesnt really work at all. When i press teh on button everything starts whirring (as it should) and just keeps doing this indefinately with no change to teh black screen at all until i shut it down at the socket. I tried removing my Hard Drive and booting it up and the exact same thing happens. Please help as this is incredibly frustrating! It just sits on this blakc screen until i shut it down, doesnt go to teh MOBO screen or anything, and the green light on the actual moitor's case that signifies its working goes orange pretty quickly (signalling that its idle and has nothing to do).