<validationRules>
    <fullName>Changing_an_Opp_to_Closed_Won</fullName>
    <active>true</active>
    <description>Only the system admin and ZZZ users
                 can update the stage to closed won</description>
    <errorConditionFormula>AND(
                             AND(ISCHANGED(StageName), IsClosed=True, IsWon=True),
                             NOT(OR($User.ProfileId == '00eA0000000RhUw',
                                    $User.ProfileId  == '00eA00000013Vro'))
                           )
    </errorConditionFormula>
    <errorMessage>You do not have the necessary access to mark an opportunity
                  "Closed Won" Please ask a ZZZ to do it for you.
    </errorMessage>
</validationRules>