Do I need a Gigabit Network Adapter for Cable Broadband If I already have a 10/100 Card?

nope... your internet connection will be the same... but LAN connection will definitely increase its speed...

You hardware will be over kill for a Cable connection if you get a gigabit card.

That is unless you do a lot of file transfers within your network. Also all internal hardware, switches, routers, etc should be gigabit if you want to see the speed.

because of the fact your question is somewhat difficult, i will could make some assumptions. once you're saying which you have a instant connection that hooks up with a cable, i will assume which you mean, your modem is asserted to the cable/DSL. And which you hook up with the modem via WiFi. If those assumptions are splendid, and your daughters computing gadget additionally has WiFi, then you definately could be waiting to connect her computing gadget an analogous way you connect yours. If no longer, then you definately've a heavily jacked up ISP. If my assumptions are incorrect, possibly you may grant some information like : who's your ISP and what's the form form of the modem/humorous black container related to the wall. If surely, you may basically connect one computing gadget to the modem at a time, then that is a basic be counted to connect your 2 desktops, making use of a crossover cable, and then going into your community connections and installation connection sharing. You did no longer say what working gadget you're making use of, so i won't grant specified information.

no, you need a cable modem! Your existing network card should work fine.

No that is the fine, and it I dont think they make any faster cards. As long as you are using a ethernet card you are set.