Both Kingston and Crucial have memory configurators that will check your computer and let you know what you need and what the max amount your motherboard supports. Of course, you could pull out the memory that is in there now and take a look at it. Remember, that you can usually buy faster memory as long as it is the same standard. Of course the computer will not take advantage of it, but you may be able to take advantage of it in a future computer upgrade.
3 different OS, so yep I\'m confused.