Upgrading to vista questions

1. Does vista make your xp key unusable after the upgrade?

2.Does upgrading remove some of the files on the hard drive being used? (Should I back up information)

1. Yes, but you can do a clean install, and keep your copy of XP out of the fray.

2. No, it is a true upgrade, so your personal files will be left intact. I would still back-up your critical files. Even if some freak thing happens, Vista dosent format your HDD during a fresh install. If there is a previous Windows install vista moves all the files from that install into a folder called 'windows.old'.