You can use the StrComp function, with vbBinaryCompare:

'  Check to see if the two passwords contain the same characters
If StrComp(Me.txtPswd1,Me.txtPswd2,vbTextCompare) = 0 Then
   '  Check to see if the two passwords have the same case
   If StrComp(Me.txtPswd1,Me.txtPswd2,vbBinaryCompare) <> 0 Then
       MsgBox "Passwords don't match"
       Me.txtPswd1 = Null
       Me.txtPswd2 = Null
   End If
End If

This is untested code.  See VBA Help for more information about StrComp.

Don,

Maybe something like this:

if strComp(password, userpassword, vbBinaryCompare)<>0 then
..... your code here.
end if

where password is the password which the usere entered and userpassword is
the password to compare it with.