I live in IRAN. I BOUGHT a lab from UAE model no. PSU30E-01K017AR.seria no.: 77935921w the windows is vista but in iran we use XP and don't have vista.How can i CHANGE its windows from vista to xp in Iran?buy a windows xp cd and reformat the COMPUTER but make sure you get all the drivers for the computer and burn them to a cd or put them on a flash drive