I have scripted FindUser.vbs to determine if a user logon name exists in the logged on domain.

The syntax for using FindUser.vbs is:

cscript //nologo <Drive:>\Folder\FindUser.vbs sAMAccountName

Where sAMAccountName is the user logon name, like Jerry.

If Jerry exists in the domain, FindUser.vbs will echo sAMAccountName "distinguishedName", like:

Jerry "CN=Jerold Schulman,CN=Users,DC=JSIINC,DC=COM"

If Jerry DOES NOT exists in the domain, FindUser.vbs will echo FindUser sAMAccountName - NOT found., like:

FindUser Jerry - NOT found.

If you run cscript //nologo <Drive:>\Folder\FindUser.vbs J*, FindUser.vbs will echo all the matching logon names with their distinguished names, like:

Jane.Doe "CN=Jane Doe,CN=Users,DC=JSIINC,DC=COM"                              Jennifer "CN=Jennifer Schulman,CN=Users,DC=JSIINC,DC=COM"                              Jerry "CN=Jerold Schulman,CN=Users,DC=JSIINC,DC=COM"                              John.Doe "CN=John Doe,CN=Users,DC=JSIINC,DC=COM"                              Jordan.Valley "CN=Jordan Valley,CN=Users,DC=JSIINC,DC=COM"
FindUser.vbs contains:
                              On Error Resume Next                              Dim objConnection, objCommand, objRootDSE, strDNSDomain                              Dim strFilter, strQuery, objRecordSet, objArgs, usr                              Set objArgs = Wscript.Arguments                              if objArgs.Count  1 Then Wscript.Echo "FindUser UserName - UserName required."                              if objArgs.Count  1 Then Wscript.Quit                              usr = "N"                              sam = objArgs(0)                               Set objConnection = CreateObject("ADODB.Connection")                               Set objCommand = CreateObject("ADODB.Command")                               objConnection.Provider = "ADsDSOOBject"                              objConnection.Open "Active Directory Provider"                              Set objCommand.ActiveConnection = objConnection                              Set objRootDSE = GetObject("LDAP://RootDSE")                               strDNSDomain = objRootDSE.Get("defaultNamingContext")                               strBase = "<LDAP://" & strDNSDomain & ">"                               strFilter = "(&(objectCategory=person)(objectClass=user)(sAMAccountName=" & sam & "))"                               strAttributes = "distinguishedName,sAMAccountName"                              strQuery = strBase & ";" & strFilter & ";" & strAttributes & ";subtree"                              objCommand.CommandText = strQuery                              objCommand.Properties("Page Size") = 99999                              objCommand.Properties("Timeout") = 300                              objCommand.Properties("Cache Results") = False                              Set objRecordSet = objCommand.Execute                              objRecordSet.MoveFirst                              Do Until objRecordSet.EOF                                  strDN = objRecordSet.Fields("distinguishedName")                                   strSAM = objRecordSet.Fields("sAMAccountName")                                  usr = "Y"                                  Wscript.Echo strSAM & " 
& strDN &
" objRecordSet.MoveNext Loop objConnection.Close Set objConnection = Nothing if usr = "N" Then Wscript.Echo "FindUser " & sam & " - NOT found." Set objCommand = Nothing Set objRootDSE = Nothing Set objRecordSet = Nothing