Error: The file “WoW.exe” could not be found. If this problem persists, you may be able to solve it by uninstalling and then reinstalling the game. If you are unable to correct this problem, please contact Blizzard Technical Support.

Fix: press windows key + r (you will get the “run dialog”), enter “regedit”, navigate to
HKEY_LOCAL_MACHINE\SOFTWARE\Blizzard Entertainment\World of Warcraft

Got a value called “install path” there? if so, you can fix the annoying error in 5 seconds.
Change the path there to the folder (including drive pre-fix) where you WoW Install is.

Re-run the patch. You are all done.

Here is an exemplary entry:

[HKEY_LOCAL_MACHINE\SOFTWARE\Blizzard Entertainment\World of Warcraft]
“GamePath”=”N:\\World of Warcraft\\Launcher.exe”
“InstallPath”=”O:\\World of Warcraft\\”
“UninstallPath”=”C:\\Program Files\\Common Files\\Blizzard Entertainment\\World of Warcraft\\Uninstall.exe”