After you deleted LW's preferences folder, did all of the settings within LW's options revert back to default?

What listening port is your LW using?

Did you make sure to remove all other Java versions installed on your computer, before you installed the latest update?

When you disabled LW's performance options, did you make sure to click 'ok' to save the change?

Have a look at the router & see whether you can find the model - if nothing's showing on top then have a look underneath. The model might start with F5D...., F1D...., F6D.... etc If we know the model then we might be able to help check out UPnP settings & also look at port forwarding.

Have you tried any other p2p apps & if so do you have the same connection problems? Some other free apps below.
FrostWire

Phex

BearShare