Hey Olywane,
I'm sorry you're running into this keyboard issue. It sounds like one of your ALT keys is stuck down on the notebook. I tested it. Even with a second keyboard plugged in, if I hold down the ALT key on my notebook's internal keyboard and try to type an 'F' on the second USB keyboard, it opens the Office button in Word.
Check both ALT keys. Use some canned air to blow any debris out that may be underneath them.
Let me know what you find. There are some software steps you could try as well, but hardware needs to be ruled out first.