Those Dells do not have ISA slots, most likely they are PCI Express or if they are older then they may be AGP. You cannot 'remove' slots from a motherboard, they are meant to be there and not removable. You can remove the cards from the slots but NOT the slots themselves, so if you wanted to you could pull out your Radeon X300 SE card, but not remove the PCI Express or AGP slot itself.