I am supposed to upgrade my boss's computer from the worthless Vista Home Premium to Vista Business. He purchased the upgrade disk. Is it necessary to do a clean install? I ask because of some time constraints. (Bosses think everything can be completed over a lunch hour, and he will need his laptop up and running before court.) Any suggestions would make my day.
Actually, Vista ships with all versions in one package and the version you install depends on the serial number.
When you install Vista, don't enter any serial and click next, you are prompted to choose what version of Vista you wish to install. You are given a 30 day grace period (MSDN/Technet get 180/60 days).
You can enter the serial you have once installed.
I would do a clean install though, so remember to back up everything first (files and any folders) then use the Windows Easy Transfer wizard to copy User Account settings and system configurations and more.
To do this Press Start > Run and type migwiz then click ok and follow the instructions.