I succeeded today!
I took three steps - of course, I don;t know which one made the difference, but I would bet it was the third:

1) I uninstalled BOINC and hacked the registry to remove any non-trivial instances of BOINC and WCG I could find- (trivial instances are things like runMRU's and the like).

2) I downloaded a fresh copy of the install package from WCG lest a bad copy was the problem.

3) I installed as administrator invoking Vista compatibility and specifying that it should run as a service AND LEFT THE DEFAULT DATA DIRECTORY OFFERED! I suspect that was the difference.

I thank both Didactylos and uplinger for their patient help. I suggest that anyone with problems running BOINC under Windows 7 do the things I have called out in step 3.