Web controls are not displaying

Question

Hi, I'm a beginner to ASP.Net I'm not able to browse my asp.net application in the browser by using http://localhost/myapp/default.aspx. It gives an error HTTP 404 - File not found. But the same runs when I give my IP Address instead of 'localhost'. The other problem is this that any web control on my form doesn't displayed when I browse it only html controls are displayed. I'll be highly obliged if someone can help me out !!! Thanx