A colour bar blue on the bottom and green on top of42" LCD

My first answer was wrong, your model is a rear projection LCD TV, not a projection tv (the tube ones). Therefore it is not an IC problem.
As already posted, it is likely that you need to change or adjust the lamp. Here are replacement in Europe, post your location to get more options:




http://www.e-av.co.uk/info.php%3Fid%3D50...">ZENITH E44W46LCD Lamp
£261.00 - E-AV Pro Audio

http://www.filron.com/uk/index.php%3Fact...">LG E44W46LCD Lamp (Original)
£219.29 - Filron UK

http://www.filron.com/uk/index.php%3Fact...">ZENITH E44W46LCD Lamp (Original)
£241.23 - Filron UK
Regards
My first answer was wrong, your model is a rear projection LCD TV, not a projection tv (the tube ones). Therefore it is not an IC problem.
As already posted, it is likely that you need to change or adjust the lamp. Here are replacement in Europe, post your location to get more options:
ZENITH E44W46LCD Lamp £261.00 - E-AV Pro Audio LG E44W46LCD Lamp (Original) £219.29 - Filron UK ZENITH E44W46LCD Lamp (Original) £241.23 - Filron UK
Regards

It is correct , you should not replace the lamp unless you are a technician or an advanced DIY. Lamp costs over US$400 and must be tested before being replaced. There may be many additional reasons why the LCD tv is displaying horizontal bars. May be a problem with some component on the main board, or a misplaced LCD display cable.

Turn off all appliances aroun your tv, if you have an option for using a traditional uhf areal use the tv with aerial only, and check if you still have the bar, alternatively try moving tv to other room. Problem of this kind may be generated by disturbance from an heavy appliance nearby (fridge, big amp, transmitter), or by a defective cable.

If you cannot get rid of the problem it may be neccessary locating a tv repair in your area.
If you want to DIY you will need to start from getting the service manual with diagrams and part list, it costs $25. Here is also a forum on problems with your model, if you ask them they may get service manual for free.

Regards
It is correct , you should not replace the lamp unless you are a technician or an advanced DIY. Lamp costs over US$400 and must be tested before being replaced. There may be many additional reasons why the LCD tv is displaying horizontal bars. May be a problem with some component on the main board, or a misplaced LCD display cable.

Turn off all appliances aroun your tv, if you have an option for using a traditional uhf areal use the tv with aerial only, and check if you still have the bar, alternatively try moving tv to other room. Problem of this kind may be generated by disturbance from an heavy appliance nearby (fridge, big amp, transmitter), or by a defective cable.

If you cannot get rid of the problem it may be neccessary locating a tv repair in your area.
If you want to DIY you will need to start from getting the service manual with diagrams and part list, it costs $25. Here is also a forum on problems with your model, if you ask them they may get service manual for free.

Regards

Agreed with ginko. In some models the lamp can be easyly changed, I dont know about this one. Agreed with ginko. In some models the lamp can be easyly changed, I dont know about this one.