Perhaps you mean you CAN'T share anything, right? (I've something made that mistake, a breakdown somewhere between the gray matter and the fingertips Happy )

Anyway, since you can get to the Internet, that shows you have the computer's Ethernet working. So your TCP/IP setup is probably not at fault. And since those other computers are able to get to the Internet also, the same is true for them.

I would look at any Firewall you have on the newly setup computer. The Firewall s permitting your reach out, but prevents other's seeing and reaching you.