This article addresses one of the tools I use in the workstation environment for virus and adware scanning/prevention.
My virus prevention/scanning tool is the McAfee Clinic from http://clinic.mcafee.com. McAfee provides a FreeScan program at http://freescan.mcafee.com that detects (but not removes) up to 25 viruses. My advice: install a virus scanner from a reputable company. If you don't have one and cannot get one, run FreeScan straight away to ascertain if you've been infected. The registered edition is $19.95 for a one-year trial and $39.99 for renewals.
The software provides periodic updates and a variety of methods for download (automatic, manual and download only). In this paranoid world, I've edited the job that checks there server to once per hour (default is once per day); you can do so in Control Panel, Scheduled Tasks. The engine requires a reboot on the first installation; subsequent updates typically do not.
Once installed, the Clinic monitors downloads, file writes and macros pretty effectively. It notifies the user when a virus activity is detected, and prompts for a scan of the system. You can set the scanner to run at off hours to ensure your system stays clean and virus-free. Scanning manually will also pick up adware and spyware, listing them as “Potentially Unwanted Programs”, prompting you to delete them.
McAfee provides conventional versions of their virus scanning software with or without media ($20 discount for download, last I checked). Some would prefer these instead of accepting their ActiveX control.