I believe the easiest way may be to use the old DOS command SUBST - but I do not know the syntax. It would substitute a non-existing drive letter (of your choice) for a directory or subdirectory (folder). The only issue here is that a batch type file (*.bat) would have to be placed somewhere (in the registry?) to run at windows startup as each time the system is shut down, it would lose the command. Attempting it directly through Vista would probably involve hundreds of registry fixes for existing programs, not too mention what would happen each time a new program/file was downloaded by someone other than yourself.