VB.NET

I have problem with an executeable file of VB.NET
namely “aspnet_wp.exe”. Because when
I build a ASP.NET Web Application and Click on Start the required Web Application did’nt open in Internet Information Server (IIS) with an error Message that “Web Application Server”. When I view the “Event Viewer” and selct the application log the error I have find is that “the required password and login name is not valid”. Please guide me or tell something else to overcome this probolem. I shall be very thankful to you