HI, you can try the below solutions
1. You can right click on project in the solution explorer, click on web tab, choose Use IIS Webserver radio button Click on Create Virtual Directory button
2. From the Visual Studio.Net 2008 command prompt run
aspnet_regiis.exe -i
and then right click on virtual directory, click properties choose
ASP.Net tab and then select the ASP.Net version as 2.0.50727 from the ASP.Net version dropdown.I hope this helps you in solving the error