Microsoft Office Enterprise 2007 - change language

Hey there.

My grandpa's computer hard drive died and we had to get a new one. Everything was installed from scratch... except for Microsoft Office because we don't have a CD (a family's friend had installed it when we first got the computer) and it's no longer available for sale on the stores.

The computer technicians installed OpenOffice for my grandfather to try, but he couldn't get used to it, so I resorted to my fav website for help and downloaded Microsoft Office Enterprise 2007 SP2 since the one he had before was Home and Student 2007, so this one would be the most similar for him to use (he had an hard time adjusting to new Office changes, even if they only update the visual aspect of the program).

The problem is, right now all office programs are in english, and my grandpa doen't understand a word. He can still do some things (mostly in Excel, since he can still recognise the symbols), but he can't use Office at its full potential. I was wondering if there's any way I can change the program's default language from English to Portuguese (pt-pt) - the spell checker is in portuguese, but the menus are still in english.