回答“Why isn't my mouse working?”I tried every suggestion on here and a couple other sites. Fn + f9 or fn + anything else didn't work. I did try fn + f3 and it worked! apparently it's the f key with the symbol that looks like a mouse and a line across it from one corner to the other (the x one didn't work on mine either). Hope this works for those who are still trying to figure this out.