VS 2010 How to update rows if exists else insert new rows in access table

Hi,

I am doing a window application using VB2010 and Access as back end.
I have tried many ways to check if the rows exists then update a particular field else insert new rows.
I am using datagridview in from1 where user able add new info (rows) and those rows will be saved in TableA and I need to insert same rows in another Table (TableB) if the rows not exists, else if rows exists then values should be updated.