Vista XP Dual Boot Problem!!

First off, I admit my computer stupidity, I'm not the most knowledgeable. I'm hoping someone can help me.

I had a Vista Home Premium and installed a XP SP2 CD. I was not familiar with what i was doing until i was half-way through the installation, and did not partition my drives or things like that. I installed my XP and thought everything was ok, except upon completion it seemed like i recieved the absolute minimum to run the OS; no programs, no network capability, etc.

My big question is how can I uninstall this XP to go back to the Vista, and hopefully later re-install it correctly?
I still have a C:\Windows, because i didn't install my XP into that folder. Instead i sent it to C:\User. I do not have a folder in C:\Windows called old folder though