We rarely realize how much we rely on a television remote until it starts to malfunction. Suddenly, we can't change channels, the volume is stuck and we have to stand up to turn the set on and off. If a remote is truly broken, it may need to be replaced. While a number of additional factors may affect the remote's ability to function, most of them can be corrected with a little troubleshooting.
Most television remotes rely on an infrared signal, which the remote sends out and the TV picks up. If that signal is blocked, the remote won't work. Check the area between you and the TV to see if anything—furniture, for example— is blocking it. Examine the area around the TV's IR sensor; it may be blocked by books or DVDs stacked in front of it. The distance of the remote from the TV may play a part in it as well. It the remote won't work, move closer to the television.
Universal remotes let you control multiple electronics at once, avoiding the clutter of numerous remotes. To function correctly, they need a specific code entered in a specific manner. If you've recently changed batteries on the remote, you may need to enter the code in again; you may also have inadvertently erased a given code by pressing a specific series of buttons. The specifics depend on the type of remote. Consult your owner's manual to find out the exact way to program in a code. If you don't have your owner's manual, check the home page of the company that made the remote; it should have the codes you need.
Nearby electronics may interfere with the remote's sensor. This can include (but is not limited to) radios, scanners, hair dryers and fluorescent lamps. Interference may also stem from other remote controls being used, which may disrupt the signal from your remote.
Buildup can create problems with the functioning of your remote. In particular, check the cover in front of the IR bulb at the front of your remote for gunk. You might also check the contacts around the various buttons on the remotes. Gently clean off any buildup with a dry cloth, or apply a small amount of rubbing alcohol to the cloth and wipe the remote clean.
If the remote is broken, you can contact the television manufacturer for a replacement. Write down the model number of the television, then check the manufacturer's web page to see if it still produces remotes for your specific TV. If you can't find it there, check eBay or similar online auction houses, or consider purchasing a universal remote, which will work with any TV.