Keyboards have an uncanny knack for becoming filled with all manner of undesirable knack. Most of it, disgustingly enough, comes off of our own hands. In addition dust and hair tend to find their way into every knook and cranny on a keyboard. You may not know it, but your laptop that you forgot to close the lid on overnight is the perfect place for cats to snooze the night away. In addition to all that, most of us are guilty of eating and drinking while using our laptops and crumbs and drips will inevitably find their way into the keyboard. It's Murphy's Law. As a result of all this, even a relatively new laptop can quickly get sticky and unresponsive keys.
There are very simple and uninvasive methods you can use to clean your laptop's keyboard. Regardless of what kind of laptop you have, a can of compressed air and a soft lint-free rag will solve most of your keyboard troubles.
Step One: Hold your laptop, carefully, over a trash can. Better yet, have a friend hold it for you!
Step Two: From 3-4 inches away, use the compressed air to blow the loose dust and hair out of the keyboard. Holding the can at an angle to the keyboard works best. Be sure not to hold the can upside down as doing so will release yucky chemicals into the air, and worse yet, into your laptop.
Step Three: Get your soft, lint-free cloth very slightly wet. It should be dry enough that, were you to wipe it across glass, the streaks it leaves would only last a couple of seconds.
Step Four: With your laptop now on a flat surface, run your cloth across the keys, cleaning the tops of them, as well as depressing each key and cleaning around them to the best of your ability.
Step Five (optional): If your keyboard is especially dirty, particularly between the keys, you can use a q-tip dampened with a small amount of isopropal alcohol to clean around and under the keys.