You can't stuff anything up by deleting the preferences
What model's your Netgear? How do you have it set up (is UPnP enabled, are you port forwarding)? If you're port forwarding, maybe set it up again (see Grandpa's post here for why)
http://www.gnutellaforums.com/showth...068#post208068

Do you see the firewall icon (brick wall in front of blue earth)?

Did the port test work?
http://www3.limewire.com:6346

Have you tried using any other p2p apps?

What's the name of your ISP? Even if they're a small local company, might be some info around about them.