ATTN: Computer-geeks: (And I mean that in the most affectionate way!)

Please bear with me, as I don't know much about computers, but would like to use Limewire...
I just bought a new Dell computer, and installed limewire, and am receiving an error message, something about "unable to open a port to listen for incoming...." or something like that. I've searched this forum, and noticed that other people have had the same problem...HOWEVER, the solutions offered are WAY over my head. I am computer-stupid, and trying to solve this is giving me a headache. Here is what I can tell you:
I am using Windows XP, I've already followed the instructions about opening a port with 6346 or whatever that means...I just installed Norton a few days ago, Mcaffee is on my computer (I don't know how it got there, it was on there when I first turned the computer on, and I don't know anything about it). There isn't really anything else on the computer, so there should be enough space...And that's about all I know to tell you

I don't know...Please help me if you can... (and remember that I need DETAILED instructions, with SIMPLE LANGUAGE...ie. no computer lingo please!!!)
Thanks, Nic