if you installed mods before you reinstalled it may not have deleted everything via the uninstall utility,
when i have uninstalled it in the past sometimes a few items are left over in the scripts folder, when you re-installed it part of files from other mods may have stayed in the install and caused problems,
Try reinstalling it again, but after uninstalling goto the Activision folder and delete the Bridge Commander folder therefor deleting any left over files that could screw up the game,
Alot of people are running BC in vista and dont have any problems so i highly doubt it would be that