Don't send students back to college without an up-to-date antivirus. If the student's college doesn't provide them with a corporate license, the free offer from Microsoft and Computer Associates was extended until February 2, 2005.

http://www.my-etrust.com/microsoft/ 

The software includes a firewall, if you don't need it, choose the custom install option and don't install it. However, if you aren't using a firewall you should install it.

If your student uses Windows XP, be sure to install SP2 as soon as it's publicly available. (At this time, only MSDN subscribers can download it.)

Note: This AV software is also on a security cd distributed by Microsoft last winter. The CD version pops up registration reminders every now and again while the download does not. :)