Who is your ISP? If it's Optimum Online, there are lots of other people in the same boat with you.

If you're not with OO, tell us your details

OS(Win XP etc)
LW & Java version (help > about LW & you'll see)
Firewall you're using
Modem/router brand & model
ISP
Connection type (DSL etc)
Where you connect from (home, school etc)
Are you sharing a connection with other computers
Is this your first try with LW

Do this port test & see what result you get
http://www3.limewire.com:6346

Make sure your firewall's configured as per the sticky at the top of this section

I have no idea what an Isp is. Not vary computer savy.
But I know I have:

Windows Xp

Limewire 4.10.3 Pro, Java 1.6.0-Beta

I have the windows firewall disabled but I also have a McAfee firewall and that is allowing limewire

If it is a motorola surfboard sb4100 cable modem

I have a cable connection from home with no other computers

I have used limewire for a year with no problems at all

I have already tryed configuring my firewall many times

And the port test worked

If you could try to explain what an Isp is that would be great. Thanks

An ISP is an Internet Service Provider. The company that you pay for your internet use

Oh ok Im pretty sure its Millenium Digital Cable.

I can't find any info on your modem supporting UPnP. If it does, make sure it's enabled within the modem & ticked within LW's tools > options > advanced > firewall config. I don't think it has an internall firewall, so that shouldn't be a problem. Are you using a router as well? If you are, we'll need the brand & model.

Did anything at all change before you lost connection? Any upgrades, change of hardware, letter from your cable company saying they were making changes?

It would be worth it to call your ISP & find out if they've started shaping bandwidth or filtering p2p in any way. Your default port for LW's not blocked but it just sounds a bit fishy. I might be wrong

Ok how do I enable UPnP on my modem?