There is a simple rule in file sharing, which applies to all p2p software.

Never ever use p2p software, without having a good antivirus installed, which you will keep up-to-date. When you download files that potentially may contain virii, also do a manual scan, just to be sure. These especially includes *.exe files.

It's really not hard. And there are free antivirus around.

Good luck getting rid of the virii.