asp.net with ADSI authentication problem

Question

Hi all, currently I am having a problem trying to get my application to login using the ADSI authentication method. Using System.DirectoryServices namespace, I tried to create an object based on the domain, username, password but still unable to authenticate it. Somehow it goes like this: public bool Validation(string domain, string username, string password) { string user = domain + @"/" + username; DirectoryEntry DE = new DirectoryEntry("LDAP://" + domain, user, password, AuthenticationTypes.Secure); if ( DE.Name != null ) return true; else return false; } it always say project this error "Bad username or password"... By creating an object of DirectoryEntry, am i already trying to log in into the AD? Do I need administrative access to the AD to be able to validate my username and password? How do I go about working on it? The provider does not support searching. Thank You.