problems with internet, emerge, and resolving

[mpeg4v3]

I recently got to college and brought down 2 computers. The second one, I had installed Gentoo on prior to coming down here, since I am a complete linux noob and wanted to learn. Everything worked fine, and I was able to emerge everything, get KDE setup, but then I emerge'd openoffice, and that error'd out after about a day and somehow that screwed up my entire install, so instead of trying to fix it I just reformatted.

The first time I reinstalled, I couldn't emerge anything. During the install, after booting from the LiveCD, it worked. However, as soon as I finished the install and rebooted into the shell for the first time, none of the mirrors worked. Every mirror it selected would time out, despite the fact on this computer, my main one running winxp, I can go to all the mirror sites. The second time I reinstalled, the same thing happened. However, this time I chroot'd using the livecd and emerge'd xfree and kde from there, hoping somehow that would fix it (remember, total noob here), but it didn't. I can't get to any web pages either.

Here's the basic setup of my computers:
Main computer (this one) running Windows XP with 2 NICs and basic internet sharing (since each student in the dorms is only allowed one ethernet jack/student) without windows basic firewall enabled. This PC is 192.168.0.1, and is set as the basic DHCP server. My second is 192.168.0.2. I can ping 192.168.0.1 from it, and vice versa. I copied resolv.conf exactly as it said, and upon inspection that file has the following in it:
nameserver 192.168.0.1
search mshome.net

The firewall here (at SDSU, San Diego State University) allows incoming connections, but no outgoing connections, except on port 80. So I can't ping any outside web sites, despite being able to go to the web sites in, say, internet explorer.

I'm at a loss as to what's wrong. I don't understand why it works off the LiveCD, but not once I reboot into the actual install. I also have no clue why it worked the first week I was here, but as soon as I had to reinstall it, it stopped working.