If you currently do not have an anti-virus program running or are no longer able to get regular updates (program is expired), you can use the Sophos program available to the HMC community. However, to use this, make sure you first uninstall the current anti-virus you have. Then follow the steps below for the appropriate operating system :

Steps to install Sophos for Windows

1. Go to your Start menu. Go to Run....
2. Type \\lurch.ac.hmc.edu\sophos. (if prompt for username and password, use 'antivirus' for both)
3. Go into the ESXP folder. (Use this folder if you are using Window XP or 2000)
4. Run the setup.exe file. (if prompt for username and password, use 'antivirus' for both)
5. Restart your computer.
6. Click on the shield icon in the bottom right corner of your screen.
7. Select Update Now.

MAC OSX instructions coming soon