[G4] Monitor Adjustment

[bob johnson]

I have a MAC G-4 , 10.4.11, 867 MHz, PowerPC G4, 2 MB L3 cache, 1.5 GB SDRAM
My problem is this; all of a sudden I cannot adust the color on my 
monitor ViewSonic Graphic Series G90mb.
It  is either too bright or too dark,  I use the utility provided by 
Apple and cannot adjust it at all anymore.
I even had a new flat screen installed and it still does not adjust, 
so I returned the monitor.
Any one have any suggestions, besides a new computer.
Thank You
Bob Johnson