We might be dealing with an EDID (http://en.wikipedia.org/wiki/Extended…) problem. Without a valid EDID, there will be no display. Have you tried a different VGA cable? Have you tried toggling the source on the monitor? I can also take a closer look via PlugDebug. Since this forum does not support attachments, I would need you to contact us directly -> firstname.lastname@example.org.
PlugDebug allows us to get a better idea of which driver versions are on the system, as well as diagnostic and installation logs, while minimizing the amount of questions we send your way when we are looking into an issue.
Please head over to -> http://plugable.com/support/plugdebug. There you will find a download link as well as instructions. Please be sure to have the display adapter plugged into the computer with its monitor attached when running this tool and attach the resulting zip file in the reply to this email. Once we have the .zip file it generates, we will get a better idea of how to best proceed.