Firefox

1. Bitdefender - virus scanner.
2. Jotti - upload file, test for viruses.
3. NanoScan - fast viruses/spyware scan. Requires ActiveScan 2.0 plug-in.
4. TrendMicro House Call - viruses, malware, vulnerabilities.

Internet Explorer (ActiveX required)

1. CA virus scanner. IE/ActiveX
2. Microsoft Safety Scanner
3. ESET scan viruses, worms, Trojans, adware, phishing, and spyware.
4. ewido cleaner for malware. IE/ActiveX
5. F-Secure -simple virus scan. IE/ActiveX
6. McAfee FreeScan virus scanner. IE/ActiveX
7. Panda ActiveScan - scans viruses, worms, trojans. IE/ActiveX

Windows Computer Updates

1. Windows Update - part of Windows operating systems
2. Secunia PSI - scans your computer for outdated software, offers updates.
3. CCleaner - deletes junk files and cleans Windows Registry
4. Intel Driver Update Utility - checks for new driver updates