Try to change the flat panel scaling to use nvidia. Open your nvidia graphics control panel and scroll to > change flat panel scaling. I used to have the same problem and I fixed it after changing the flat panel scaling to use nvidia.

it was on monitor scaling, i put on nvidiar scaling now and still the same black space, then i turn off the pc, put dvi and power cable off, put dvi on, put pc on stand by, conect monitor power cable e fire up pc, still same problem :smileysad:, is on nvidia scaling setting now.

uninstall driver, run driver cleaner on safety mode, reinstall driver and still the same. now i perceive the black part is also on boot and bios screen, so it can't be a driver issue, the monitor doesn´t have settings to fix this, any suggestions?

Try to change the screen resolution to 1680 by 1050 @ 60 hrz and try to change the dpi to 120. If this does'nt  work maybe your monitor is defective.