One of the most secure way to ensure that no one snoops around your hard drive is to encrypt it. Although it might sound complicated, it’s actually very easy thanks to a program called TrueCrypt. A lot of programs charge serious money for the same job that TrueCrypt does but this is completely open source and does it pretty well, if a bit slowly.
The program can create a virtual encrypted disk within a file and mount it as a real disk or encrypt an entire hard disk partition (such as USB memory stick). Intruders will face two walls of password protection before they are able to access files.
One advantage of this is that you run all those P2P apps from an encrypted drive and not worry about getting attacked from the other end. Any intrusion is met with heavy encryption that only the most determined hacker would get through. Even with a firewall, your PC is particularly vulnerable when running such programs but encryption gives you an extra level of security.
The user guide takes you through the process very quickly which is no more complicated than defragging a drive although expect to wait at least a few hours for the process to complete. Note that it won’t slow down the performance of your hard drive afterwards. A great free tool to protect you at home or on the move with your USB drive.