Monitor lost colors

[multy]

I Have a Power Mac Dual G4 running OSX 10.4. I use a monitor Dell P991...All of a sudden the collors desapeard like it had only 256 collors...I testetd another monitor and the problem still there...These two monitors worked perfectly until today...I found out that diconnecting the small cable adapter that conect my monitor to the computer fix the problem but disconnecting the monitor output cable from the adapter does not...but as soon as I reboot the computer the problem comes back...Please Help... Thank you

 

[symphonix]

Have you checked System Preferences -> Displays and made sure "Colors" is set to "Millions". On occassion, if the monitor becomes unplugged or the connection comes loose, this setting will automatically revert back to 256 colours.

 

[multy]

yes I did .... It's set to "millions"... All the cables are well atached ... What is really intriguing me is why when I unplug and plug back the video cable the colors come back ... but that must be done at the computer port ... If I do it at the junction of the video adapter cable it doesn't work...could it be a hardware problem...the adapter or even the video card...?