How do i delete the row which has the old date for the same productid in case we have multiple rows

pls help

productid -- orderid -svt -hbgm
787 -- 12-may-2005 -2345 -4444
787 -- 13-may-2005 -789 -- 878
786 -- 12-juane2004 -222 -v569
799 -- 14-may 2003 -768 -p234

the query shoudl delete 787 -- 12-may-2005 -2345 -4444


pls help

thanks