[PappyAnn]

I have a sb5100 and i was wondering if i can use the usb and the ethernet to two different computers

[mduell]

No. I think your best option is to buy a router (~$25 these days) so you can connect both comptuers via ethernet.

[ghporter]

I agree with mduell. Routers are inexpensive, easy to use, and overcome a number of otherwise very difficult issues, sharing a connection being one of them. On top of that, typical home/small office routers (all of them I've ever heard of) implement Network Address Translation which helps protect your networked computers from outside intruders. It's not a "real hardware firewall," but along with your OS X firewall, it's pretty darn good!