VBA code to change value in a drop down

I have 4 sheets, each with a table of values. Each table has a drop down box which causes the values in the tables to change.

On a separate sheet i need the total of the these 4 tables of values but when the drop down lists show a specific value.

I thought of maybe recording a macro or using some VBA code to do this, but when i start recording and then change the value in the drop down box, the macro doesn't seem to have recorded anything.

Any suggestions on the best way to do this?

I have attached an example file.

The detail tab contains the data. The summary tab displays it.
On the summary tab you can see that there is a drop down box that let's you choose quarter. This then displays the relevant data in the table.

My file has 4 of these summary and detail sheets, one for each department.

Say i need a total for solid for 4Q2007. I can't just do a sum calculation of cell C10 in all my summary sheets because the drop down in one of the sheets may be on 1Q2008.

My first idea was to create a macro that set each drop down to Q4, but i wa snot successful.

Any ideas?

Anyone got any ideas?

Anyone got maybe just the code in VBA to change the value of a drop down?