2 common problems with Voewsonic PNP Monitor is it is not detected even you installed the appropriate driver, common issue discussed regrading this problem :
-Windows identify it as non-Pnp Monitor
-Maximum resolution of 1024 x 758 instead of actual resolution.
-Could not wake up after sleep
-Stuck with VGA output
1. Shut down your computer.
2. Plug in both DVI and VGA cable into your Monitor and computer (Video Card)
3. Turn on your computer and let it boot into windows.
4. After that shut down your computer
5. Unplug VGA cable (DO not unplug DVI cable)
6. Unplug monitor for 10 seconds (remove the power chords)
7. Plug in the monitor and turn on the computer.