hello I have laptop from dell and another from asus my dell laptop ( vostro 1400 ) came without any OS so i used xp pro for it. but i see there is untouched dell oem dvd for vista home/p w/sp1 , i download it and test it , but it say i have 30 days only is there any mistake i did ? ps: this dvd is original oem , not pre activated dvd .. thanks