1. Try and learn some grammer
2. Please, for your sake learn something about comptuers in general, Windows XP, Windows Vista, their operating systems. And yes they can be installed and un-installed easily.
3. Yeh, Vista isn't that great but if your going to get it with your pc, it's better than buying a copy of XP and going backwards, because vista DOES have advantages. That is of course if you were planning on
buying vista

.
Oh, on top of all this i suggest one thing:
GET A MACC
That is of course assuming, that you know what a macc is?
Edit: With 2 gig of ram mate, there not much you
can't do