another monitor on this computer?
If this monitor tests OK on another system and the drivers are up to date, I would suspect the graphics card.
But before going that far, a few comments;
When you updated the drivers did you reboot the system afterwards? If not, then try that now.
Also, when did this happen, and what occurred when it did? If it was in fact a driver update, try rolling back the driver.
Has this Pavilion ever had the case opened and the dust bunnies blown away from the fans and the vents?
If nothing helps, then I think you are looking at a failing graphics card and since it is integrated there is no replacing that, but if the system has a spare PCI slot you could add a video card to it. In fact the CNET video review in the link below suggests that is possible;
http://cnettv.cnet.com/hp-pavilion-a6400z/9742-1_53-50001892.html
Mark
Please help--I run a small non-profit and one of my staff's monitors is displaying incorrectly and we can't figure out why.
HP Pavilion a6400z
windows vista 32 bit
Integrated graphics using nVidia GeForce 6150SE
The colors are the monitor are dull and incorrect. When the monitor and cable are hooked up to another computer, the display is perfect. We have tried resetting all display properties and downloading all the drivers for the graphics card. Does anyone have other suggestions as to how to solve the problem?

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