Erm... I really hope I'm interpreting things wrong here but um... Okay I'm not exactly a Zune expert but I am pretty good with computers. First off, purchasing Limewire Pro is a mistake. I would never download music off Limewire. Anyways, when you loaded music on your Zune from your friends you had to use the Zune software right? I'm assuming you installed the Zune software and know how to upload music from your computer to your Zune via the Zune Software. Limewire is just software to download music (and bad at that) and the Zune software is what you use to interface the Zune hardware with your computer to get them connected, basically. The Zune software is different from Itunes but the best way for you to get music from your computer to Zune is with the Zune software (hopefully installed and updated to like 3.1 or whatever the current one is) and you need to go to settings - collections and then add the folder your music is in on your computer. After that in the settings you will see the options software, device, account in the top left corner. Click device and by default it should be Sync Options. Use smart sync and have everything set to the first one. All music, all videos etc. Don't use manual unless you know what you're doing. Next, plug your zune into your computer with the USB connecter if it's not already and it should sync with all the files in those folders you added.
I hope this helps because if it didn't I have no idea what you're talking about.