VGA 2 DVI Adapter - Ground Loop Issue?

I recently purchased an X-Gaming MAME Cabinet that comes with a Wells-Gardner D9800 Digital Arcade Monitor. This supports a maximum resolution of 800x600, but is being ran at 640x480 for MAME.

Everything is working perfectly except for the fact that the monitor seems to be attracting a very annoying ground loop (or so I assume). This isn't so bad on lighter, more detailed games. But on stuff like Donkey Kong/Galaga is it extremelly noticable (2 large gray horiztonal lines moving slowly down the screen, distorting straight lines).

The computer being used is a tower I built about 3 years ago that has an ATI Radeon 1900. This has 2 DVI Ports, as well as an S-Video connection in the middle. The monitor only has a VGA port. So I am using the VGA-2-DVI adapter (small end-to-end plug) that came with the video card.

Both the computer and monitor are plugged into the same surge protector. This is a pretty expensive surge protector (Belkin) so I'm kind of assuming it is not the issue (i have heard cheaper ones can cause ground loops).

I have attempted to plug the computer/monitor directly into the same wall outlet, as well as plug them in seperate ones.

So I guess my question would just be for people to throw out suggestions as to what might fix the issue. I was thinking of trying a VGA-2-DVI cord itself so no adapter would be needed.

Any help/thoughts would be appreciated!