>On my form I have a field holding an Installation Number(from a table, one side). Each installation can have mutiple dash numbers(from a table, many side) which I display in a combo box. Each dash number can have multiple assemblies which I display in a grid. Each Assembly can have multiple details which I display in a second grid. How can I get the grids to update when I select different value in the combo box. Note: I do not have any relationships set up in my tables.

Steven,
Either set relations or if they're SQL things :
.Recordsource = .Recordsource
Cetin