Change computer from French to English and back on...

Question

I have an international student from the French-speaking country of Benin who is staying with me in USA. She has an Acer Extensa 5220 with OS Vista basic. Her laptop is entirely in French. She did not bring her manual and she forgot how to switch to English so I can troubleshoot any more problems (we had an earlier problem resolved here) She is unable to translate (into English) sufficiently any technical computer terminology. We do not want to permanently change it into English but temporarily so I can help her with technical problems. I am a Window XP user so it makes it even more difficult for me to help her because I do not recognize where to navigate etc. If she had Windows XP I possibly could do it even in French. She is totally non-technical and about all she can do is read and send emails and surf the web and (I assume) write papers for school.
Thank you I would appreciate any help, I do not think that this is a terrible difficult one. Thanks again.