Before fixing the buttons, imagine the principle of their work. Here everything is simple. The button is a plastic, silicone or rubber base that has an inbuilt metal contact. This contact is in contact with the working circuit, causing a short circuit and the corresponding reaction in the apparatus. Most often broken as the time base. In this case, the main task – to save the contact. Plastic buttons often crack or crumble from too frequent or improper use. To repair laptop keys better that way.
To start evaluate the extent of the damage. Remove the broken or cracked key and remove it from the laptop casing her pieces, if any.
If the key can be glued, try to do it using superglue. Miss them joints, applying the glue as thin a layer as possible. It is very important to establish contact at the same place.
If the key to bonding is not subject, try to make it independently of epoxy resin. To do so, except for the epoxy, you will need plasticine to make the shape. The completed form is fill with epoxy, put in her contact (this is often a small metal transactions sufficiently large cross-section). Ensure that contact was properly installed.
Having made a key start for its installation. Just keep in mind that done this way the key may have irregularities. So first grind it to fine sandpaper.