As u r running Win XP Pro on ur D: with in installed. The u will be able to install Linux on ur C: with no problem. However I would recommend backing uo everything on ur D: cos IT does tend 2 delete everything on all partitions!!. This is because u have to install Linux on first, Linux creates the duel boot partition. U can have xp on their first but i wouldn't risk it.
Trust me i'm a bastad!