Problem Description :
When I login to eb web I need a tickbox - "Use my Windows Account to log in"
Solution :
Go to eb Web Application Manager
Select the webpage, one for which the tickbox does not appear, go to Authentication and from the drop-down select Windows Authentication as the Authentication Provider and then check if all the required functionalities(in the next tab) are check marked and click Ready to Install(highlighted as 2)
If Windows Authentication is already there and still there is no tickbox while logging in then:
Go to IIS-> sites-> select the site ->Authentication-> enable Windows Authentication and ASP.Net
You will have to reset IIS from command prompt. go to cmd-> iisreset
You can also try restarting eb services.
Go to Services-> eb Service manager-> Restart