404.3 Denied by mime map

<configuration>

<connectionStrings>
<add name="StudentsConnectionString1" connectionString="Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\Students.mdf;Integrated Security=True"
providerName="System.Data.SqlClient" />
<add name="FacultyConnectionString1" connectionString="Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\Faculty.mdf;Integrated Security=True"
providerName="System.Data.SqlClient" />
</connectionStrings>
<system.webServer>
<security>
<requestFiltering>
<fileExtensions>
<clear />
</fileExtensions>
</requestFiltering>
</security>
</system.webServer>
<system.web>

<compilation debug="true"
optimizeCompilations="true"
targetFramework="4.5" />
<httpRuntime targetFramework="4.5" />
</system.web>

</configuration>

this is my web config in a website i'm building vs2012...

I was initially getting error 404.7 which is i guess solved by including <clear /> tag as in above. But now a new error has its bad-eye on me. I have seen many solution regarding 404.3 ..I even have gone to services enabling asp checkbox...restarted my pc...tried to change some settings in iis manager but still the same error 404.3 is repeating .. I'm naive to IIS and i just wanna concentrate on my project errors rather than this...:P ..So please help ASAP.