WOTLK update broke the file

So after the Lordaeron realm restart i got a game update and after downloading the file it started installing then it gives me an error "wow.exe cannot be renamed to wow.exe.trash"

I unticked read only on the folder, same error. So I removed the wow.exe and backed it up and the update worked but now i cant start the game because it is saying im not connected to the internet. Been trying all kinds of stuff but seems like I have to redownload 18gb.....

P.S there is a launcher now but thats saying it needs to be in the same folder as the game even though it is.

delete the client and get new one, I guess you tryed to log-in with your email rather than AccountName, so youe client started to update to Cataclysm