My wii remote or sensor bar won't work. The wii connects to the TV, the home screen comes on but I can't make any connection between the tv and the remote. The remote itself works (power comes on) and I borrowed a friend's sensor bar to make sure mine wasn't broken. But nothing happens...what could be wrong

Make sure that your Sensor Bar is connected properly and that there is no damage to the wire connect it to the Wii.

You may have to place the Sensor Bar else where and reconfigure it to work again.

Ref: http://www.nintendo.com/consumer/systems/wii/en_na/ht_system.jsp
-Connect the Sensor Bar under Wii Console in the left menu.

Make sure that your sensor bar is straight, and not on an angle. You may have to contact Nintendo if this problem occurs.

Try this following steps: 1. Check to make sure the Sensor Bar cord is inserted into the back of the Wii console and the Sensor Bar is centered above or below your TV screen. 2. Make sure you are using fresh batteries in the Wii Remote. 3. The Wii Remote Controller should be used between 3 to 10 feet from the TV. 4. Make sure no objects are blocking the signals between the Sensor Bar, the Wii console, and the Wii Remote. 5. Check for interference from infra-red light sources, such as candles, sunlight, fireplaces, and stoves. 6. Radio frequency interference may cause the Wii Remote to work erratically.

After getting everything out of the box, decide on where you want to put your Wii. It should be near your TV and near an electrical outlet. You can either lay the Wii flat or sit it on its side. If you’re laying it flat, move on to step 2, Connect the Cables. If you want to place the Wii in a vertical position you should use the Wii Console stand, which is the gray base unit. Attach the console plate to the bottom of the stand, put it on your shelf and then place the Wii on it so the beveled edge of the console aligns with the beveled edge of the stand.
There are three cables that connect to the Wii: the AC Adapter (a.k.a. power cord); the A/V connector (which has three colored plugs on one end); and the Sensor Bar. The plug of each is distinctly shaped, so each cable plug will only fit in one port in the back of the Wii. (The two small, same-sized ports are for USB devices – ignore them for now). Plug the AC Adapter into the largest of the three ports. Plug the Sensor Bar plug into the small red port. Plug the A/V Cable into the remaining port.
To connect your Wii to your television, find the sockets on your TV that, like the A/V Cable, are colored yellow, white and red. The sockets are generally on the back of the TV, although you might also find them on the side or front. You may have more than one set of ports, in which case you can use any of them. Insert each plug into a port of the same color.
The sensor bar can be placed either on top of your TV or right below the screen, and should be centered with the middle of the screen. There are two sticky foam pads on the bottom of the sensor; remove the plastic film covering them and gently press the sensor into place.
Next, simply plug the AC adapter into a wall socket or a power strip. Push the power button on the console. A green light on the power button will appear. The remote comes in a rubber jacket, designed to protect it, which you will have to partially peal off in order to open the battery door. Put in the batteries, close the battery cover and pull the jacket back on. Now push the A button on the remote to make sure it is working (a blue light will appear at the bottom of the remote).
The Wii remote that comes with your Wii is already synced up, meaning your console will communicate properly with the remote. If you have purchased any additional remotes, you’ll have to sync them up yourself. To do this, remove the battery cover from the remote and press and release the red SYNC button inside. Then open the little door in the front of the Wii where you will find another red SYNC button, which you should also press and release. If a blue light goes on at the bottom of the remote then it is synced up. When using the remote, slip the Wii remote wrist strap around your hand first. Sometimes when people are waving their remote around it slips out of their hand and breaks something.
Turn on your TV. Set your TV input for the input channel your Wii is plugged into. This can usually be done through a button on your television remote generally called “tv/video” or “input select.” Read any onscreen text. This will be either a warning, in which case you can press the A button, or a request for information, such as whether the sensor is above or below your TV and what the date is. Point the remote straight at the screen. You will see a cursor similar to the mouse cursor on a computer. The “A” button does the equivalent of a mouse click.
Once you have answered all the questions you are ready to play games. Push a game disc into the disc slot; the illustrated side of the CD should face away from the power button.
The main Wii screen shows a bunch of TV screen-shaped boxes, and clicking on the top left one will take you to the game screen. Click the START button and begin playing.

Make sure that the Sensor Bar is setup correctly:
Check the cord on the Sensor Bar for any frayed wires or kinks, and verify that the Sensor Bar is free of obstructions.
Verify that the Wii Remote is being used between 3 and 8 feet directly in front of the TV, and that the Sensor Bar is placed properly (see Sensor Bar setup).
Verify that there are no bright light sources, including sunlight, behind or near the TV, shining towards the Wii Remote or reflecting off the TV screen. Also verify there are no heat sources (such as electric, propane or kerosene heaters, flames from fireplaces or candles, stoves, etc.). If there are bright lights shinning directly behind the TV or on the screen, turn the lights off.
If problem persist your Wii Remote need service.

Hey Jack, How many remotes are you able to connect at a time? If you have multiple remotes try turning the ones you know that work off, and putting them in another room(so you know they will not try to connect). Then try connecting with the bad one. If that doesn't work you might have to sync the remote: hold down the red sync button on the wii, located next to the sd card slot, while holding down the red button on the remote, located under the battery cover on the back. Now try connecting. If it still doesn't work, the LED lights in the sensor bar might have burned out, this happens a lot when you keep your sensor bar directly on your tv without the stand(the tv gets hot and burns out the lights), a lot of people do this because the stand looks bad. Go buy a new sensor bar, they sell them at wal-mart for $20, plus they're wireless, so you don't have to worry about that thin little wire popping. Test the new wii bar, if it's still not working, then you're remote is just worthy of getting returned.
hope this helps! -cj

Your sensor bar is definitely burned out, you can get a new wireless one at wal-mart for $20. Often wii sensor bars burn out because people put it directly on the tv instead of using the stand, the tv gets hot and the LED lights in the sensor bar burn out. If you want make sure that it's the sensor bar that's broken, get a video camera and video tape the sensor bar while it's plugged in and the wii is on, if you can't see four LED lights on each side then it's broken.

(1)
Verify that the cable bar sensor is plugged into the back of the Wii console and that the sensor bar is properly aligned with the centre of your TV screen.
(2)
Check that the Wii remote is synchronized with the console using the POWER button on the remote control to turn on the Wii console. (The POWER button is the white button with the red symbol which is located in the upper left corner on the Wii remote.) If it does not work, try to synchronize the remote control, then turn the console and controls that respond correctly to commands.
(3)
Verify that the distance between the Wii remote and the TV display to be between 1 and 3 meters, that there are sources of intense light that can interfere with the proper functioning of the remote (read Guidelines game for Wii for more information ) And that the sensor bar is placed correctly (see Setting up the sensor bar). Avoid the presence of sources of infrared light as electric stoves, gas propane or kerosene, candles, fireplaces, stoves or other heat sources close to the console.

If the steps described above do not solve the problem, the sensor bar could have a problem. Read the following instructions:

On each side of the sensor bar are five infrared lights that located the position of the Wii remote. If these lights do not work, the cursor on the remote will not appear on the screen and you can not step through screens of settings. To see these lights, you must look on the LCD screen of a digital camera or a mobile phone. Verify that the sensor bar is connected and that the Wii console is turned on, and then framing the bar sensor so that it appears on LCD camera or cellphone. If you see five infrared lights on each side, the sensor bar works. Maybe you'll need to slightly adjust the position / tilt the camera or the telephone, but is rather easy to see these lights on the LCD screen
;)

possibly, or low batteries in the remote. Try placing the bar under the tv if its above at the moment, or vice versa if currently below. Also make sure sensor bar overhangs tv slightly too...