bought used iMac, previous owner wiped it clean
I bought it as a gift for my pc fresh newbie dad, he has a new apple ID also, how do we get mountain lion on it using his new ID? given that the previous owner wiped it clean.
the previous owner bought it new in July this year (2012) and I bought it last week (dec 2012).
I understand that the OS will belong to his ID but cannot work out how to buy it through the app store using his ID on his wiped clean Imac.
I already own a mac but bought mine new so have no experience with this part.
Any help much appreciated to save a fresh pc convert from becoming too frustrated and returning to the dark side !!
iMac, Mac OS X (10.7.4)