Hi Robert,
The Graphics card was the first place I looked. 
I am using an ASUS EAH 4350 Silent DI 512MB 2/A. I think it also goes under the name ASUS ATI Radeon however because I believe one of those companies bought the other. Alternately I tried plugging directly into the Motherboard’s GPU output but the problem remained. Based on pooling your info and mine I would not think the problem is NVidia related.
HTH,
Joey