Sony prjection tv 5 years old hardly used eithier

Has the set been knocked or had a bang in any way, these rear projection tvs are very tempermentle to slight knocks, as you can knock the crts out of line, also the crts have a cooling gel that is located on the top of them, these after a while cloud up causing a very poor picture, if this is the case, then they will have to be replaced, just have a quick look at them you will be able to see if its the gel problem, look directly down on the crts (MAKE SURE THE SET IS TURNED OFF THOUGH), hope this is of some assistance.