You can reload on a fresh format as many times as you like, so that will not be an issue.
Another thing you can do is just remove the XP listing from the boot sequence. Since you had XP on first you will need to do a repair on the 7 install to rebuild the boot file. and then open up Disk management in windows 7 Then you can format the XP partition and then use the extend feature to extend your main partition into the old XP partition.