I was able to install Vista SP1 using the directions provided, and that did indeed solve my issue. Thank you very much for your help!

I know it's kind of annoying when people post to ask questions that have already been addressed, but FWIW I used the search function before I posted, and it didn't turn up anything useful searching for "High School Musical 2" for some reason. It never occurred to me that this could be a Vista problem!

Anyhow, thanks again for the help. You guys rock.

Cam