DHCP works with my quicksilver. And I upgraded w/out choosing to format. Try asigning an ip address that say your buddy has (and ask him to disconnect while you try this) manually to your osx.1 box, and configure any routing/dns... see if that works. If it doesn't, there may be something fundamentally wrong with 10.1, not necesseraly in dhcp.
BTW, /sbin/ifconfig -a will show all network interfaces.
hope this helps.