Head unit turning on then going off

[Digitalghost]

Well I took my CD player out to see if I could see what was wrong with the bloody thing. There wasn't a disc in it so I put it back in the car and now the door doesn't open and it doesn't come out. And the radio comes on and then goes off after a few seconds.

So now I can't even listen to the radio! How do I get it to work again?

 

[whitenemesis]

double check you've correctly reconnected the fibre optic cables