Are you trying to use BitTorrent? Those ports are used with BitTorrent.
You might want to block WAN Requests or Disable ICMP requests within the router. Someone might be hitting your router and making is disconnect.
In almost all cases you can plug in a router and just go without really needing to configure anything.
If you're using bit torrent and it's not working, you can log into the router and forward those ports. When you open BitTorrent Windows XP firewall shoudl prompt you to Unblock this app, which should allow those ports to work fine. You can check to make sure the problem is unblocked via windows firewall. - Contro Panel - Security Center - Windows Firewall - Exceptions Tab.
Newer version has 1 additional port opened. Check the FAQ for info on making bit torrent work better over NAT and what ports you need forwarded.<P ID="edit"><FONT SIZE=-1><EM>Edited by riser on 05/20/05 11:29 AM.</EM></FONT></P>