Need Key Sequence To Turn On/Off Acer Green Keys Function

I have an acer aspire and in some programs (Picasa 3 -the picture management program) the functions on the green keys operate when you press the keys. Most green key functions are mathematical or alpha characters for languages other than English. I never use those functions so never learned the key sequence to turn them on and off. I am on holidays in another country and didn’t take any manuals – so I can’t look it up. If anyone knows how to turn the green key functions on an off I would be very grateful if you could send me this information. My main problem is that I can’t get the possessive form of a word since I can’t access the ‘ symbol n Picsas3.