There is a product, called GetRight, that manages downloads and you can pause them and it stops in case you need to. It'll also pause if for some reason your internet disconnects.http://getright.com/
is the URL for it. There's a free version that doesn't ever run out. I use it all the time because I, unfortunately, can only get dial up where I am and it's a life saver. And it's for Vista too, so you'll be okay.
"I would feel more optimistic about a bright future for man if he spent less time proving
that he can outwit Nature and more time tasting her sweetness and respecting her seniority."
E. B. White (1899 - 1985)