|My bet would be the VGA-DVI adaptor is causing the problem.|
You either need a monitor with a DVI input or a graphics card with a VGA output, so you don't need to use an adaptor.
It's the monitor and graphics card which aren't compatible (connectivity-wise),
In any case, being forced to use a VGA-DVI adaptor rather defeats the purpose of using a DVI output in the first place.
Too bad you didn't buy a card which had both VGA & DVI outputs instead of dual-DVI. DVI may be superior, but not when your monitor doesn't have it.
You made a bad choice for the monitor you currently own.