If you stuck at Updating Blizzard Agent

I run the battle.net.setup.exe and accidently choose the ‘Chinese’ language setting. The installation process stuck at the ‘Updating Blizzard Agent’.
Because the Chinese server is shutdown and there will be no update.
Re-launch setup won’t solve the issue because language setting won’t appear again.

You need to delete this Register Key:
HKCU\Software\Blizzard Entertainment\

And run the setup again, just choose the language other than ‘Simpified Chinese’, then it will work (at least on my machine:)

Hope it will help.