I'll concur with the TCP/IP problem diagnosis.. If you've got another computer's drive mounted on your desktop and can retrieve files from it, then you have bi-directional ethernet up and running, AppleTalk, I assume. So it's really localized to just the TCP/IP software or it's configuration. How to fix it? (insert blank look here) I'd suggest one of the OSX webpages like OSX-zone or maybe Macfixit, or macslash, this is deep-geek territory if you've got the settings right, and since the iMac works, it seems you do. But just to make sure, swap ethernet cables between machines, swap ports on your hub/switch/router, powercycle everything on your network