Some file-sharing programs may install malware that monitors a user's computer utilize and then sends that data to third parties. Files you download may also hide malware, viruses, or other unwanted contented. And when you install a P2P file-sharing application, you might be requisite to install "adware" that monitors your browsing habits and serves you advertising.
Malware and adware can be hard to detect and remove.

Before you use any file-sharing program, get a security program that includes anti-virus and anti-spyware safety from a vendor you know and trust and make sure that your operating system is up to date. Set your safety measures software and operating system to be updated regularly. Make sure your security software and firewall are operation whenever your computer is connected to the Internet. Delete any software the security program detects that you don't want on your computer. And previous to you open or play any downloaded files, scan them with your security software to detect malware or viruses.