C:\Program Files\World of Warcraft\Launcher.exe" -opengl
For example say WoW is installed to E:\World of Warcraft\
The start in entry should be
"E:\World of Warcraft"
Also goto your WTF folder and delete the config.wtf file and restart WoW it will reset graphical settings etc. Make sure you dont pick any settings your GPU can't handle.
Also make sure you dont start it up in DX11 beta mode if you dont have a DX11 GPU card (if you did set this it will be in the config.wtf file you will delete anyway)
[Edited by DABhand, 1/13/2011 1:43:35 AM]