The WoW.exe defaut location is C:\Program Files\World of Warcraft\World of Warcraft\WoW.exe

But I have 32 bit wow installed on my PC And I do not know if your 32 bit or 64 bit. the core will work both 32 bit and 64 but as for wow.exe I do not know? So I would make a back up of your WoW.exe Frist before you replace.
And if you already replaced and your getting a wow error. delete the WoW.exe in the default folder and do a wow repair.

This could be new problems We run into if so Ill amke a repack that will include the extra .dll if you getting .dll errors and a 64 bit update for the 64 users.