Television and Home Theater

I haved a 61 inch toshiba big screen and my remote doesn't get signal to the t.v. anymore. they told me thats what the problem could be. i cant find the remote senor does anyone no where the remote senor is at.

i have a 32" sharp and everytime i turn it on it comes on but right away turns itself off and i can not do anything till i unplug it and then it does the same thing

i was given a mitsubishi model cs2657 and it turns on but i cant find any channels. all the switches produce some response onscreen vol,tint,color, etc... they all display on a background of snow, all except the channels. i cannot get a dvd to play as i cant find the correct channel. I have a universal remote but don't know how to connect it. any help with these two probs would be so appreciated   thanx