help pls..asp server is not running??

hi, i'm a newbie in asp.net and also this is my first post..
i make a new project on ASP.net application on vb.net and i got an error it says:

Visual Studio.net has detected that the specified server is not running ASP.net Version1.1. U will be unable to run ASP.net Web applications or services...

i have no iea about this error..
please help...