Answer to: fixing broken C key, it has come completely offCheck Laptop Keyboard Key Replacement Videos. They have video tutorials on all models of laptop. Take your pick and i even bought a single key from them to replace my broken 'enter' key last month. Good Luck!
Answer to: How to take off a keyboard key ?You can also check this link which has videos on how to remove and replace a key for any brand / model of laptop: How to replace Laptop Keyboard Key Video