If you're going to install 7 anyway, stop bashing your head agains the wall trying to clean up Vista first. Dump all your info - docs, pics, music, the works - to two different places (redundant backup, don'cha know). Format the drive, and do a fresh install of 7. It'll be faster, cleaner, and faster. Did I mention faster?
Edit to add: I forgot you were installing the 7 upgrade, not a full product. So scratch what I just said.... maybe. Might still be faster and cleaner to back up your data, wipe the drive, do a clean install of Vista, then do the 7 upgrade. Maybe the upgrade-o-philes can shed more info on this.
Brad