Visual Studio .NET - "Visual Studio NET has detected that the specifi

"Visual Studio .NET has detected that the specified Web server is not running ASP.NET version 1.1. You will be unable to run ASP.NET Web applications" 

this err i install iis and vs.net

A very common but weird error we get when trying to open asp.net applications using visual studio.net is "Visual Studio has detected that the specified Web Server is not running ASP.NET version 1.1. You will be unable to run ASP.NET Web applications or services." 
 
This will paralyze you particularly if you have been working on some applications for sometime and one fine morning when you open vs.net, you get this message.
 
The resolution is simple, just re-register the aspnet user account.  To do that, type the following from your command prompt:-
 
%windir%\Microsoft.NET\Framework\v1.1.4322\aspnet_regiis.exe -i

the above is based on .net 1.1 version. for other versions, just change the version number.

This will install the aspnet user account and register the asp.net with the IIS.

1) ensure that ASP.NET 2.0 is enabled in IIS 6.0 (not "prohibited").
2) ensure (for ASP.NET 2.0 only) that there is no "app_Offline.htm" file in the web application folder.

Try running this - substituting xxxxx for your specific version (browse the Framework directory)

C:\WINDOWS\Microsoft.NET\Framework\v1.1.xxxxx\aspnet_regiis.exe -i

Had the same problem today