"Do you think if I connect the laptop to the netzero modem then connect the modem to the hub could get the laptop online?"
If the Netzero is a USB-only DSL modem you probably need to replace it with a router -- which will connect to computers via ethernet (or in most cases now, wireless).
You may still need to add an ethernet port (PCMCIA or USB version) to the old Toshiba (if I understood you correctly).
When trying to connect two computers via ethernet (Cat 5) you have to disable the firewall on each before starting.