tuningassitant only black screen

[piotre]

I just saw yesterday that some channels I never watched via GBPVR since setup are not tuned/set up correctly. So I wanted to rerun tuningassistant to check the channels but it only shows a black screen. It will stop at channels that I know are broadcasting and diplay th window to write down the channel number but the screen is black (all the time, not grey dissling but black). Anybody got an idea?
Is it possble that the PVR 350 is locked by GBPVR somehow (I did kill all processes related to GBPVR)?

Thanks,
Piotre