Windows issue, will this Vista software work for upgrading?

Hello,
So here is my issue. I just built a new PC and, instead of buying a new OS I decided to install an oem xp pro disk I had laying around from dell(stupid me). Well, the key for the computer it came on won't register it on my new computer(obviously), and I need to get a new OS. I was wondering if this OEM Vista software would be able to upgrade my xp to Vista, or if I would be forced to reformat the hard drive and delete everything off of it.

http://www.newegg.com/Product/Prod [...] 6832116204

There isn't much on the hard drive at the moment, just xp, some cpu utilities, and a couple games(Counter strike source and guild wars).

Any help will be greatly appreciated, and any other recommendations are welcomed too.

Thanks