I would use BootitNG to remove windows xp and get the partition on your hard drive ready for linux. It can be found here: http://www.terabyteunlimited.com/index.htm
I would recommend backing up your windows xp with it just in case you feel like going back at a later time. Just put the backup file on another partition. Anyway this is what I would do. I have been using bootitng for years and it makes system restores take about 15 minutes.
The XP has never been activated. I can’t do anything through windows. It won’t let me log on or access explorer.