I have a Packard Bell Imedia 2215 pc (completely standard) which the other day decided not to boot up with screen remaining blank (no signal). Pulled hard drive out and put in caddy and all is fine as i can expolre entire drive. When start up button pressed power come on, fans spin up, hard drive can be heard but then nothing! Put an external graphics card in incase onboard was at fault but same problem. Any ideas at all?