If you like to rotate your monitor 90 degrees to get more code on the screen but it just will not stick this may be the issue, SP3 for XP.
The issue I had was with a Dell monitor, on a Dell Optiplex with an ATI video card. I had downloaded the latest ATI driver (the whole Catalyst setup) from Dell’s site. It installed fine and I could access the settings in the Catalyst Control Center to rotate the screen, but the rotation would never stick. Ended up I needed version 8.4 or higher. So I downloaded the driver again, this time from ATI. The driver from ATI gave me version 8.54. After that it worked perfectly.
This post on TechNet gives some info as well.