webdev. webserver.exe application error

Question

hi all...  am just trying  to run a sample asp.net web application with default page...  but when i run the application , it shows

" webdev. webserver.exe application error"  after that again

it shows " Unable to Connect To ASP.NET Development Server".........

         pls help me to solve this problem.... am not able to run any asp.net application.....thanks in advance......