Samsung SyncMaster 740N Auto-Adjustment Locked

I wasn't able to adjust many settings on a Samsung SyncMaster 740N monitor. I was only able to adjust brightness and contrast. The image was shifted and scaled, resulting in a non-1:1 ratio between output and actual pixels, causing blurry images. I found the solution at http://www.fixya.com/support/t553848-samsung_syncmaster_740n_17_auto. Surprisingly, all you have to do is hold down the Menu button! I wonder what the lock does, then?