Let's say you were using the defualt settinga and no personal files were shared. Is there a way that someone would create a virus or malware to share my documents folder or some other folder on the limewire network? Or how would they go about it
See my previous reply. Yes, it's possible, depending on the software and how it's settings are stored.
Like I said, it all depends on the intent of the malware. Back when Limewire/those kinds of P2P software were popular...sure, it could be likely that they would change your sharing/directory settings... but I wouldn't say very likely.
A piece of malware's point would be to exploit other security flaws that exist on the system so that it can leak your info out, get you to click on something to download more malware/give out your credit card info or other account info, download more malware by themselves without your intervention, or just leave backdoors open and let other malware in at later times.