Are you using the ADO control? Data Environment? DAO?
Did you set the datasource, member, and fields of the other textboxes that you want to display the other info?

It should go something like this:
(set at design time)
DCombo1.Rowsource=ADO1
(All of the datamember properties only need to be set if you are using the data environment otherwise just leave that out)
DCombo1.Rowmember=Household
DCombo1.ListField=Surname
Text1.datasource=ADO1
Text1.datamember=Household
Text1.datafield=Address
Text2.datasource=ADO1
Text2.datamember=Household
Text2.datafield=HouseholdId

In the click event of the DCombo1 have something like this:
Private Sub DCombo1_Click(Area As Integer)
If Area=2 then
ADO1.Recordset.filter="SurName LIKE '" & DCombo1.text & "'"
End if
End Sub

The filter makes only the records matching the criteria set show up in the recordset. So if there are more then one of the surname you would have to .MoveNext through them or filter by a unique field maybe HouseholdId instead. But it will update all the controls linked to the same recordset, thus changing the address and Id accordingly. Try that!