I AM USING VB6/MS ACCESS AND ADODC WITH DATAGRID CONTROL

set your combobox key field or value to something you want to search for in your datagrid. when the user changes the state of the combobox, simply fetch either the key or value of the currently selected combobox item to do the search on the datagrid. in regards to the last part of your question, you can load another control with its own datasource and search it based on which row or rows your first datasource returned.