As noted in one of the earlier posts, apparently not everybody is affected. Many but not all. So whether your problem is your isp or something else I don't know. But it certainly points in that direction. Try Bearshare Lite
http://www.filehippo.com/download_bearshare_lite/ & see if you're able to connect. If it is your isp, then they might only be targetting LW & only for selected users. It's hard to know how they're approaching the issue if the problem is them. It's not uncommon for an isp to target only specific users. Stief, an experienced member of this forum could tell you about it. How after threatening to go to another isp after he had a free trial with another isp, that all of a sudden after telling his isp, they stopped the shaping of his LW bandwidth. I've read similar reports here & other forums.
It seems they aren't blocking ports. However they might be shaping or blocking along a port. Not likely, as the program they probably use will detect the LW softw. But you could try changing ports. Such as 1111, 3500, 80, 4008, 1203, 10000, 15189, 22817, 443, 427, 34599, 40475, 64049. ie: Go to LW's menu bar, Tools>Options>Advanced>Firewalls. Change the port there. But to change the actual connection port, you may need to set it to manual port forwarding. And change both the listening & connection port. I haven't worked with a UPnP router so I'm not sure if you need to change both. Change the port, press apply button. Then reconnect. ie: go to File>Disconnect, wait a minute, then file>connect & give each one at least 15 mins to try to connect. And experiment with downlding to see what speeds you get. Again, the magnet link is probably a fast guaranteed way to test the speed of your downlds.
I thought Napster had closed down. Do you find many downlds with it? I presume they're not files found on a server as before.