By retail client, you mean my purchased WoW on the Blizz server? If so, I changed my resolution to 1920x1080 full screen (from windowed full screen). After closing it, I opened up WoW.exe that I extracted from the 1.12 client Rar and the message I get is "Hardware Change. Reload default settings?" with a yes or no option. I tried both choices and both times the 1.12 wow.exe displayed as a square. Afterward, If I open the 1.12 WoW.exe without making changes to the purchased WoW, the hardware change message doesn't pop up. I have noticed that my Nvidia control panel displays a message suggesting changing my resolution after I close the 1.12 wow.
* I just tried changing my resolution to the Nvidia suggested 1366x768 from 1080i 1920x1080. My TV (monitor) displays the change after it's made. When I open the 1.12 .exe I noticed that it displays 1024x768, but when I minimize it to my desktop, it shows 1366x768. Not sure if that will help.
Update* 6/17 Ok I'm not quite sure what happened, but I woke up this morning and I suddenly went from having 4 resolution options to 20. This was not the case after doing the step you told me, but now it seems to have worked. Thanks for the help!