4. When I installed NTG2.5 there is no sound.
This is because the unit was configured for Harmon Kardon sound system, you need to find an independant with Star Diagnosis and the 'development' mode settings who is willing to try and reset the unit. There is a rumour that NTG2.5 can be set to default settings by doing the following: Turn off unit. Press and hold the ON button until it comes on and turns off again. Now Press and hold the ON button and at same time rotate volume control clockwise. When you hear a noise, release ON button. If this works for you please let us know.