combo box population

[novitaun]

Hello gotta problem handling comboboxes

I got 2 combobox in my spreadsheet and I want to add a macro to them. What I want is the following:
In order to populate the seccond combobox I need to select a value of the first one. Depending on the value selected the data loaded onto the seccond combobox is one range or annother.
What I try to do is select a combobox, then associate a macro to it. A rutine is created on a name as following:

Sub combobox1_change

End Sub

How can I refer to both comboboxes?
how can I unload data from the combobox?
how can I load new data into the combobox using one range or annother depending on the value selected on the other combobox?