1 computer consists of
1 motherboard
of which, the motherboard can contain
1 (or more) processors
1 (or more) memory simms/dimms/dram,etc
1 video card
1 (or more) network cards
1 modem
1 (or more) hard drives
etc...
Then when you sell the "computer", all appropriate parts need to be removed from inventory from their respective item codes. Am I following your needs here?