Authenticate domain and local users

From: Jacek (Jacek_at_discussions.microsoft.com)
Date: 04/27/05 

Date: Wed, 27 Apr 2005 13:17:02 -0700

Hello
I have the following problem:
I'd like to check whether entered user, domain, password are correct for
domain user. Second need is to check local user credentials. What .NET
functions should I use?