putting a comp together, almost done. it seems that my windows XP cd has vanished and my microsoft word cd has run out of CD keys. do you guys know the deal about these cd keys? how many times can you install XP or word? i erase my HD and reinstall every so often and i dont want to spend too much money if i have to rebuy cds all the time. anyone have info on this? where do you guys buy XP and word? thanks!