It was a good thought. I disabled all Windows Media Center services, rebooted and performed a channel scan, but not one channel was found, all with 0 strength and 0 quality. In other words, no change.
Sub, your willingness to help is very appreciated! If I'm becoming a nuisance please say so. I just find it hard to believe that I'm the only HVR-1600 user with Vista. I would have hoped this question was more academic by now
After having vista for about 12 hours, I decided that it did not offer me much in terms of an upgrade, so I had no problem reverting to XP. If this does get resolved, I'd consider another go at it.
So apparently my XP was on the hairy edge of stable, so I needed to do a clean install (I was due anyway). Rather that redo XP, I went once again with Vista.
FWIW, the clean install made a world of difference and the machine is working very well.
The bad news is I have the same issue as orginally reported... No HD/ATSC video or sound; no ATSC signal is recognized. Analog still works fine, so I will limp along until some fix is made (GB-PVR, Microsoft or Hauppauge).
If anyone can suggest anything beyond what has already been discussed, I would greatly appreciate it.