I have a toshiba 44nhm84 DLP TV. I switched from cable to in house/attic antenna. I can not get sound or picture. My other none Toshiba tv works just fine.

SOURCE: Programming remote to toshiba Tv

Depending on the universal remote you can usually program the remote without knowing the codes. One way is to turn on the television, then follow the basic programming instructions for the remote, but instead of entering a code, hit the power button over and over again until the television turns off.
I hope this helps.
Ken

SOURCE: Toshiba 44nhm84

This happened to my 44nhm84.  The problem turned out to be the light tunnel, which is an arrangement of four little mirrors mounted between the lamp and the color wheel inside the light engine.  One of the mirrors had come loose and was blocking the light transmission pathway.  I used a little dab of glue to hold the mirror in position, and the problem was fixed.
I've read about other reports of problems with the light tunnel, but usually they say that only one side of the picture is dim.  I think it depends on which end of the light tunnel gets blocked.  If the end towards the condenser lens is blocked, then the blockage will be imaged on the screen.  If the end towards the lamp bulb is blocked, the problem is well out of the focal plane of the lens, so a general dimming is the result.

SOURCE: How to replace Power Supply in Toshiba 44NHM84 44" TV

Since this is a DLP type set, there is a lamp and ballast involved. When the set shuts down, are there any indicator lights on the front? If so, check the owner's manual for an explanation of their meaning. Typically, the lamp can cause this or the ballast. If either of those are the problem, usually the lights on the front panel will indicate it.

Keep us posted.
Dan

SOURCE: Shadow down right side of screen on a toshiba 44NHM84 44" DLP television

shadows at the bottom of the screen sound like moisture that was "wicked up" between the screen layers and dryed out leaving a stain. DO NOT get these screens wet, use nothing but a damp soft cloth; just a few drops of water running down the screen can cause a fairly large stain. Some people have suggested that they may be professionally cleaned, but the risk of damage is too great on the user level.

SOURCE: Toshiba 44NHM84 has no picture just red flashing standby light

during transportation your TV was suddenly shock. then causes your TV lose connection on main circuit board. trust me!