Reseating the video card can sometimes clear up your video issues

* Go here
* Under Systems, choose your type and model
* Open the Owner's Manual
* Click Adding Parts or Tech Notes, or opening the computer cover or Removing and Replacing Parts
review this procedure
* Power off the monitor and the computer
* Disconnect the monitor from the video card
* Open the case case
* Remove the retaining screw or lift the lever
* remove and reseat the video card
* Replace the screw or press the green lever down
* Replace the cover
* Power on the monitor first, then the computer