Thanks for providing so much information to help you solve your problem (sarcasm). Let me guess:
You have no DVD recorder, er how about you have no recordable DVD in the drive, er, how about it is not switched on.
Some serious questions
How is sky connected to the DVD recorder ?
Do you use a Scart lead, if so does it go from the Sky box to the DVD recorder, then from the DVD recorder to the TV ?
Has it ever worked ?
Have you read the manual that came with the DVD recorder or sky box for setting it up.
Without more info nobody can answer your question