ohh :PPP sorry , i just solve your first issue how to set criteria , sorry again :P
now change your code like this
dim Query as string
Query = "Select * from T_INCIDENTS1 where 1=1"
'now for example you have 2 textboxes , txt1,txt2 , for you filter
if txt1.text<>"" then
Query = Query & " And Incident_Postcode='" & txt1.Text & "')"
end if
if txt2.text<>"" then
Query = Query & " and Incident_DMA='" & txt2.Text & "') "
end if
Hope this time it works fin9 :) sorry , again
Regards