1. Right click the WoW Launcher that you use.
2. Go down and select "Properties"
3. in the "Target" box, it 'should' say "D:\Stuff\World of Warcraft\Launcher.exe"
4. Add -d3d11 to the box (adding a space after the ...exe" part)
5. Should look like this... "D:\Stuff\World of Warcraft\Launcher.exe" -d3d11
6. Click apply.
7. Open your game as normal, and enjoy!
P.S. you may have to turn off your "Hardware Cursor" if your mouse does not show up after this, just log out, go back to Properties, and delete the -d3d11 part, re-open WoW, turn off the "Hardware Cursor" Log back out, and repeat steps 1-7.
P.S.S To find your "Hardware Cursor" while at the WoW login, or inside the game, go to your options menu, and select the "Advanced" tab, then Select the "Hardware Cursor" (3rd one down) and select to disable it. Click apply and your done.
EDIT: Personally I have the NVIDIA GeForce GT 425M w/ NVIDIA Optimus and I have found that this fix works.
Special Thanks to Nox from my guild who has helped me in countless hours with finding a fix! Thanks buddy.