My Dev Environment is SharePoint 2010 on WIN 7.
Now when I Sign-in with my account and use Manage Web Application link, on the Top Ribbon none of Button is enabled. I can not create Web APP nor Extend it. When I select web application from list, some button are enabled but not all. Also I can see role as Contributor.
This is due to security problem on Win 7. Please follow below steps
1) Login as ADministrator
2)
Open User Account Control Setting from Control Panel \System and Security \Change User Account Control settings
and set the Slider bar to "Never Notify " as shown in below picture(cmd:msconfig);