Replaced the Apple Remote Battery

If you're using the remote with an Apple TV

When you use the Apple Remote with Apple TV, make sure of the following:

If you’ve paired Apple TV and an Apple Remote, make sure you’re using the paired remote:

If you’re using the paired remote and the Apple TV status light flashes white, the problem isn’t with the remote.

If you’re using an unpaired remote, the Apple TV status light flashes amber.

If you’ve paired Apple TV and an Apple Remote, and you can’t find the paired remote, set Apple TV to work with any remote by pressing and holding the Menu and Previous/Rewind buttons for 6 seconds.

Point the remote directly at Apple TV.

Make sure the IR receiver on the front of Apple TV isn’t blocked.

Another remote may be paired with Apple TV. You may want to unpair the remote and then pair it again.

If Apple TV displays a picture of a remote and a warning () symbol, you need to replace the battery in the remote. See "How to replace the Apple Remote battery" for steps to replace the battery.

If you're using the remote with a computer

When you use the Apple Remote, make sure of the following:

You are using the remote within 30 feet of the computer.

You have an unobstructed line-of-sight to the front of the computer.

You are pointing the lens end of the Apple Remote directly at the front of the computer.

Your computer is on and awake.

The "Disable remote control infrared receiver" checkbox in the Security pane of System Preferences is NOT checked.

Note: If you see "Unpair" available in the Security pane of System Preferences, another Apple Remote may be paired to your computer (pairing allows only one Apple Remote to control the computer). You may want to unpair the remote and then pair it again.

Make sure your application works with Apple Remote

If your Apple Remote doesn't seem to be working with an application on your iMac, make sure that the active application is one that can be used with the remote.

Use a digital camera to test your Apple Remote

A digital camera or DV camera with an LCD display can be used to see if your Apple Remote is emitting a signal. You can use the built-in iSight camera or FaceTime HD camera on your MacBook or iMac computer. Infrared beams are invisible to the human eye, but most digital camera and video cameras use Charged-Coupled Device (CCD) chips or image sensors that are sensitive to infrared light.

To use an iSight or digital camera to test your Apple Remote, follow these steps:

Turn on the camera so you see a live picture through the LCD. If you are using an iSight or FaceTime HD camera, turn it on by opening the video preview window of iChat.

Point your Apple Remote toward the lens of the camera.

Press and hold the Menu button on the remote while looking at the LCD or the video preview window.

If you see a faint blinking light coming from the Apple Remote on the LCD or the video preview window, then the remote is working properly.

If you don't see any blinking light on the LCD or the video preview window, replace the battery in your Apple Remote and then test it again with your computer (see this article for instructions).

If you've replaced the Apple Remote battery but still don't see a blinking light in the video preview window, contact Apple technical support (1-800-APL-CARE in the U.S.) or take your Apple Remote to your local Apple Store or Apple Authorized Service Provider (AASP) for service options.

http://support.apple.com/kb/HT1722#