Good suggestions from Jonathan and Bitt there, definitely worth trying.

But before you try those, Doug, please answer me this:

Is the troublesome PC with Vista upgraded to Service Pack 1 yet? If not, please do so, then see if you have the same problem. If you still have the same problem, then try the stuff Jonathan and Bitt are suggesting.

(I know it takes longer to upgrade to SP1 than it does to try the things Jonathan and Bitt are suggesting. I'm talking academic curiosity here, I want to know if this was simply an SP1 bug that got fixed.)