Vista is a OS. Cant just install it like a game. You would have to format your PC to install it. Unless you have a partition available to install it on.
It wont be on you add/remove apps since you cant just install it under XP. You have to install it on its own. This is to take place of XP no to install under it.
No offense Gameover but if you dont know this about Operating Systems then i would steer clear of Vista for now. Too many bugs in it to try and get it to work right.
I just installed 5308 myself. Not to shabby. WMP11 crashed everytime i tried to run a movie. IE7 was okay. Other than that the same options i seen since Beta 1.