How do I fix the m key on my keyboard?

I dun know what is wrong with my keyboard!for example , if i write m it's come out 0.if j=1. if i put fn key it's work. without fn key it's not work.my computer is sony laptop.

Normal Keyboard: 1. Snap it back on. xD 2. If first step fails, use glue. Laptop Keyboard: 1. CAREFULLY remove the least used key on the laptop (Example: the `~ key). Examine the key that you have just removed (Do NOT take it out) closely, and reassemble the broken key retainer (in your hand) exactly as the one in the key slot you have removed to look at. Once you have done that, snap the ratainer (carefully and in one peice) back into the broken key slot. Press the key cover firmly and steadily onto the key retainer (and the same with the key you have removed to look at). If none if these work, take the keyboard into a computer/technology store, such as Best Buy. Hope I helped!

Try with gluing it on. Just make sure not to use to much of it. A little should do. Use glue made especially for plastic objects.