You are correct sir. You will not need to buy a new install of XP. If you have any problems with activation after installing, just give Microsoft a ring on the toll-free number that will be offered upon an unsuccessful activation. You will be give a bunch of numbers (your installation ID) to give to some dude in India that will then read back another bunch of numbers and there you go. You will probably be asked a question like "...and how many computers is this license of XP installed on?" The answer is always, "Just one." Good luck!