DECLARE curSQL CURSOR FOR
SELECT 'EXEC sp_change_users_login UPDATE_ONE, ' + name + ', ' + name
FROM sysusers
WHERE issqluser = 1 AND name NOT IN ('INFORMATION_SCHEMA', 'sys', 'guest', 'dbo')

OPEN curSQL

FETCH curSQL INTO @SQL

WHILE @@FETCH_STATUS = 0
BEGIN
print @SQL
EXEC (@SQL)
FETCH curSQL INTO @SQL
END