Reinstalling OS (Vista) on new hard drive

you dont need to purchase a new license for windows if you are simply replacing the hard disk. you can use your existing product key, but you will need the windows installation disk.

Alright, the reason I ask is because I once had to repair a Win XP Home edition OS and it made me re-enter a key after repairing the OS, and the existing key I had wasn't being accepted, this was a few years back (On XP Home edition), any thoughts?

correct, you must use the installation media type for your key. if you have a dell laptop for example the windows key will only work with a dell oem windows disc. If you have a retail version of windows you must use a retail product key as the one printed on the laptop will not work.

Great, I was just about to ask if I can use my OEM vista business on a dell laptop that needs a new hdd to install Vista Starter. I didn't know if all versions of vista are on the dvd.