I just received an old dell inspiron 8200. the kid that had it installed some new widows program. He doesn't know what he is doing. Now the thing works real slow and I can't get it to install windows XP. I have the original disk that came with it. And professonal version if I need to go that way. But it won't let me do it.I'll show you what it says then maybe you can guide me in what to do. Is there a way to take off the old windows first then put on the one I want?