Not sure why you should all of a sudden have speed problems. Sounds a bit suspicious.
Let's do some speed tests. Do a couple to be sure. 1.
http://www.adslguide.org.uk/tools/speedtest.asp & 2. Choose your area:
http://www.t1shopper.com/tools/speedtest/
See
http://www.wayxcable.com/support.html#1
Good idea to disable your XP firewall. XP firewall & Norton FW have been known to interfere with each other. Configuration for Norton FW see:
Configuring Norton Internet Security
I don't know whether your Belkin router uses UPnP or not. If you know you can tell us. But I am aware it may require a port to be forwarded (may be why you're getting a False incoming bug test report.)
If you do decide to forward a port on your belkin you will 1st need to set up a static ip in order for it to work correctly.
1. Set up a Static ip. 2. Forward port 6346; see:
Guides for the Belkin F5D5230 which also explains how to set up a static ip. 3. Within LW:
Manual port forward instructions & sample image & 2 posts after that.
By the way, did you try deleting your LW preferences folder. This can sometimes make a difference.
Also, is your modem set up for USB or ethernet. USB can have issues b/c it may draw power from the computer, utilise the comp's cpu, & struggle with heavy traffic depending on brand & model & usb type.
I didn't see a policy paper on your isp so I'm not sure about their attitude with p2p. If I remember, I'll see if I can find it tomorrow.