Screen Problems w/DVI

I have a computer that I have been running to my flat panel LCD for about a year now with no problems. During this time, I was running a DVI to HDMI cable. Now I need that HDMI slot on my flat panel for the Blue-Ray player. I bought a DVI to DVI cable and installed it. Now my screen has green interference all over and is very jumpy. I don't believe there is a problem with the computers DVI slot because it was fine with the DVI to HDMI cable. Both DVI slots are DVI-D dual and I am running a DVI-D cable. Is it possible that it is a resolution problem even though I have it on the same resolution that I was using when I was using the HDMI slot on my LCD? Thanks for any help-Nick