System.DirectoryServices.DirectoryServicesCOMException: Logon failure: unknown user name or bad password.

http://stackoverflow.com/questions/400872/c-active-directory-check-username-password

Resolved my issue by using "Imports System.DirectoryServices.AccountManagement"

Project was working well in XP but not in Windows 7

Replaced:

Dim domainEntry As DirectoryServices.DirectoryEntry

Dim searcher As DirectoryServices.DirectorySearcher

Dim results As DirectoryServices.SearchResultCollection

Dim domainLogin As String

Dim fullName As String

domainLogin = User.Identity.Name

'Strip off domain prefix

domainLogin = domainLogin.Substring(domainLogin.IndexOf("\") + 1, domainLogin.Length - domainLogin.IndexOf("\") - 1)

domainEntry = New DirectoryServices.DirectoryEntry("LDAP://domainname.com", "domainname\username", "Password")

searcher = New DirectoryServices.DirectorySearcher(domainEntry, "(SAMAccountname=" + domainLogin + ")")

results = searcher.FindAll()

with:

Dim domainEntry As DirectoryServices.DirectoryEntry

Dim searcher As DirectoryServices.DirectorySearcher

Dim results As DirectoryServices.SearchResultCollection

Dim domainLogin As String

Dim fullName As String

domainLogin = User.Identity.Name

'Strip off domain prefix

domainLogin = domainLogin.Substring(domainLogin.IndexOf("\") + 1, domainLogin.Length - domainLogin.IndexOf("\") - 1)

Dim context As PrincipalContext = New PrincipalContext(ContextType.Domain)

Dim foundUser As UserPrincipal = UserPrincipal.FindByIdentity(context, "username")

domainEntry = CType(foundUser.GetUnderlyingObject(), DirectoryEntry)

searcher = New DirectoryServices.DirectorySearcher(domainEntry, "(SAMAccountname=" + domainLogin + ")")

results = searcher.FindAll()