Selecting Combo Box

[ziedin]

I’m using two combo box which is their data related with
each other in tables.
e.g.
Items Store
Software Lotus SmartSuite
Software Microsoft Office
Software Adobe Photoshop
Hardware Monitor
Hardware Mouse

I want to click at combo box number one, which is in
field “items” in table. I click the software and then I
want when I click the next combo button, which is in
field “store” in table, the items in that group will
appeared and when I click another button I can open the
one database which is I link to that data I have choose.