How to Fix Viewsonic Monitor not Detected

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

Solution:
1. Shut down your computer.
2. Plug in both DVI and VGA cable into your