Installing IIS on Windows 7
Follow the instructions in http://razibdeb.wordpress.com/2011/01/18/how-to-install-iis-on-windows-7 with the additional step of ticking on the IIS Management Console in the Web Management Tools in Step 4. This will ensure the IIS Manager is also installed.
If IIS is being installed after .NET Framework 4 has already been installed then you will need to make some additional configuration settings to IIS to get it to run properly (and not give errors in your website app).
Configuring IIS for .NET Framework 4
Open a cmd window (using Run as Administrator)
cd to C:\Windows\Microsoft.NET\Framework\v4.0.30319 and run aspnet_regiis.exe -i. (this will install ASP.NET v4.0)
Open IIS Manager and click on the Server name
select ISAPI and CGI Restrictions and check that the ASP.NET v4 entries are set to Allowed