Vista Ultimate 32 and my Samsung 906BW LCD Display Issue!!!

When I change any of my display settings (Brightness, Contrast and so on...)
my pc seems to accept the changes, but after about 20-30 minutes the settings
go back to settings prior to changes. I tried the monitor on a XP Pro pc and
the settings stayed to what I changed them to. I moved the vid card from the
Vista pc (not keeping changes) to the XP pc (keeping changes) and the changes
stayed fine. I also tried vid card from the XP (working pc) to the Vista
(not working) made changes to the display settings and sure enough, after
20-30 minutes they defaulted back to prior to any change. So, having said
all that, Vista does NOT work with this LCD, XP has no problems with this
LCD and with the different vid cards. Has anyone experienced anything
simular to this???

Thanks
fvlmasl2