Searching files in c# winform

See more:

WinForms

C#3.5

authentication

I am trying to list all Directory and file of C:

I tryed with
Directory.GetDirectories(dir,"*",SearchOption.AllDirectories)

but it throwing error

System.UnauthorizedAccessException was unhandled
  Message=Access to the path 'c:\Config.Msi\' is denied.

i want my program such that it continue its search except that files which required Authentication.