You may need to configure whatever firewall you're using to allow a Remote Assistance session. Windows Firewall in SP2 and ICF in RTM/SP1 I believe come preconfigured for this sort of thing, while with ZoneAlarm, McAfee Internet Security, and other third-party firewalls, you would need to configure Remote Access in Program Controls to be able to access the Internet and act as a server.
UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040804 Donzilla/0.6PR1 (like Netscape/7.2; wml/1.3)
Laptop: Turion 64 X2 @ 2GHz, 2GB DDR2-667, 100GB HD, ATI Radeon X300, 15" LCD, Seven Ultimate RC