I had a look on the net helen, and it looks like they only do a student rate on Microsoft Office XP - unless I'm very much mistaken. There web page regarding student licensing is: http://www.microsoft.com/uk/education/microsoft-licensing/student-licence/ and there no mention of Win XP Pro - still it might be worth giving them a call like Martin suggested.
Don't even think about an "upgrade" . Bite the bullit and do a fresh install. Best way is to Install it to a second hard drive using FAT32. Then you can pull all your data off the first drive. This will give you a dual booting system....