As long as you have access to the old disk, try to save all your personal files.
By the Vista install disk, do you mean one that either came with your laptop or a factory default disk that you were persuaded to create? A generic install disk will produce a leaner Windows, but you'd have to get all the drivers from the manufacturer's site. Also remember that some preinstalled programs can't be downloaded like Nero or other burner, and Cyberlink or other dvd viewer with codecs.
Be careful with static charges.