I know someone will tell me it's a repost, but yeah. Anyhow..
AutoIt3 is needed so you can edit the script. So, go to AutoIt v3 - Automate and Script Windows Tasks - For Free!, get that then you gonna wanna download the script here. Now right click launch.au3 press 'edit script'. You need to edit the following lines.
Send("ACCOUNT")
; Put you account name there
Send("PASSWORD")
; Put you password there
Run("C:\Program Files\World of Warcraft\WoW.exe")
OPTIONAL!!! If you have WoW in a different place you got to change it!
If it's a repost, I apologize, sorry! :O
SOURCE CODE
Run("C:\Program Files\World of Warcraft\wow.exe")
Sleep("7000")
; ^ Can be changed, 7000 = 6-7 sec's
Send("Account")
Send("{Tab}")
Send("Password")
Sleep("15")
Send("{ENTER}")