Im not sure if they are on the same partition, can you tell from this info?
No, I cannot tell, but if YOU don`t know I would say they are on the same partition. You would have had to create another partition during the reinstall of XP and you would know if you had done that.
I`m afraid there is no way to uninstall one of them. The only thing you can do is to reinstall. Trying to remove one will only result in problems sooner or later.
Please read the tutorials and be sure to format the partition this time. It is all explained in the tutorials.