I had a similar probelm when I had Sky installed. My home phone and broadband was working fine until the Sky box had to be plugged in. This caused my Broadband to drop out. Now, since I can live without TV more easily than I could live without a computer, I called Sky.
They suggested that, given I don't (and never will) use Pay to View, I could disconnect the Sky box from the telephone. This I have done and everything's fine.
Cheers
Whirls