My 23″ Dell SP2309W has a native resolution of 2048×1152 and worked fine until yesterday when I tried to update the driver of my ATI Radeon HD 5700 graphic card. After updating, the highest resolution I could select was 1920×1080 and I was unable to set the resolution back to the native 2048×1152 resolution. This was driving me crazy, because everything was all blurry in 1920×1080 🙁

The problem seems to occur when you have multiple screens connected to your PC; in my case I have my Dell monitor and my Samsung TV connected to my desktop. Before, my Dell was my primary and my Samsung was my secondary screen, but after the update my Samsung became the primary and my Dell the secondary. Apparently, after updating the drivers, ATI’s Catalyst Control Center sometimes selects a different screen as your primary which results that my PC wasn’t showing up the native resolution of my 23″ monitor. To make it worse, your screen is duplicated across both screens, so it’s not apparent that the index of your screens are changed or what so ever.

Anyway, to fix this, just disable your 2nd screen or make your monitor; with the higher native resolution, your primary! Easy as that, but it’s not very obvious 🙂