* What specific Dell monitor? the dell u2412m
* What specific computer model, desktop/laptop? custom built computer, pretty sure this is not the issue
* What operating system? windows 7
* What video card? radeon hd7950
* What video out ports are available on the video card? 2dvi-d 1dp 1hdmi
* What video out port are you using from the video card to what video in port on the monitor? the issue first occured while using displayport, switching to dvi-d did not resolve the issue
* What cable are you using to attach the video card to the monitor? read above
* Are you using the Dell supplied cable? I stopped using it for dp
* Press the monitor Menu button to open the monitor OSD (On Screen Display). The bottom of that screen should show a resolution. That resolution should match the monitor default resolution. it does.
* What is the monitor serial PPID number?* 
* What is the monitor serial PPID number? I do not see any "PPID" on the back of the monitor
* Can you post a video of the issue? I could but the steps involved would be painful
* Full description of the monitor issue? the monitor was working fine then I clicked a youtube link and it suddenly went to a white screen with intermittent black lines and a horrible (seemingly) refresh rate issue. after restarting the computer the image is fine however the horrible refresh rate issue remains. I have unplugged the cable from the computer and have done the self test and the problem remains