the specified password for user account root is not valid or failed

I have Visual Studio 2015 + SQL Server 2014 installed on my PC. Now i'm trying to install WordPress through WEB PLATFORM INSTALLER 5.1. I'm following the thread https://codex.wordpress.org/Installing_on_Microsoft_IIS but while installing it gives the error the specified password for user account root is not valid or failed

is there anything conflicting with installation?