Holypie~
This can be accomplished in a multiude of ways. But it will also depend on a few factors.
1) Depending on the game , unless you REALLY want to have F1 as a mapped key for the game, you COULD if it's allowed by the game(most if not all games will allow this) , to remap the key to something else just for when your in the game. This WILL NOT effect the normal function of the key when you exit the game.
2) Depending on your keyboard, there MIGHT be a button called "Function Lock" or something similar, my old MS Ergo Keyboard had this, if you fiddle around with that you might be able to use the F1 key in game with out it popping up the Windows Help.
3) You could also get into windows registry ,, if your comfotable doing that , if not there is a program or 2 out and about that I happened to come across that you CAN remap any of your particular keys.
Thats just naming the most common alternatives you have.
Hope that helps.
~LoneWolf