2400MP - Green Cast to Projected Image

My Dell 2400MP Projector had been working fine for several years using a VGA cable connected to a laptop. Projector's 2 yr warranty ( from Sept 2008 - 2010 ) is expired. I only use a VGA cable from laptop for connecting.

Projector's settings are all Factory Default with Display in PC Mode with Signal Type Selection of RGB. Lamp life appears to be only about 1/3 used ( about 150 hrs ). Projector's Test Pattern is perfect - showing all colors solidly. Image on laptop is perfect as well.

It recently developed following problem : Projector's displayed image has an overall green hue to it. This green hue ( cast ) of projector's displayed image can be removed by switching Signal Type from RGB to either other option( YCbCr or YPbPr ), which results in the displayed image being a grey scale image.

OBJECTIVE: Return Projector's operation back to showing complete full color presentation from laptop.

IF the VGA cable tests out OK ( which I'm looking to do with another projector connected to my laptop ), are there any suggestions as to what might be fix to this problem - other than buying a new one?

Thanks to anyone that provides helpful info on this issue.