have you checked your refresh rate, on a few nvidia drivers lately i've found the refresh rate resets to 60hz, and on my 21" crt that screws with the screen size/position settings. when changing back to my normal rate its fine. (i dont want to change my monitors settings because i use my 360 on its second input and for me ive got a perfect match between pc & 360 - at the moment it just a flick of the input selector)
intel i7 3770k @4.4, ASRock Z77 Extreme 4, 16GB Corsiar Vengance 1600 ram, ATI 5850 BE, Antec 1 Case, Antec 1 550W PSU, emu0404, 120gb agility3 ssd OS, 2x60gbvertex2raid0 Games, 3 TB total sata2 Data. win7 x64.