Please help with NO-Boot issue ( X51 )

Hi, my son has a Alienware X51 r1, but with the newer power board. everything was ok until today, yesterday i upgraded to Windows 10 and most things were ok, except the odd game not working. Today i started to re-install his games and the next thing it said there was a hard-drive issue?

I unplugged and plugged the hard drive back in and now the X51 wont boot up.???

the power turns on and the fan's start, but after that NOTHING. no boot screen, nothing.

i've tried unplugging everything...

Please help with NO-Boot issue ( X51 )