As above, I've heard some pretty nasty things about Geek Squad service. I hate that they've screwed you.

Can I ask what operating system is on the new computer? You might experiment with using Firefox instead of IE (of course, you'll have to do the whole reboot/reset thing one more time at least to load IE so that you can dl Firefox *cringe*) and see if maybe it's something in IE's unsupported code fighting with your LAN. What is the error message? And if you're over it and just want to not think about it, that's fine, too, I'll hush.