Antivirus:

The following are free Anti-virus solutions for your personal Windows based systems. Note: Installing multiple AV scanners on the same system could cause conflicts.
Microsoft Security Essentials This free anti-virus tool provided by Microsoft for consumer Microsoft Windows Operating Systems.
AVG Free AVG Free is the Anti-virus tool preferred by many of our colleagues. It does have live scanning which is what most end users expect from an Anti-virus tool.
ClamAV Windows We prefer ClamAV due to its Open Source nature and high detection rate. However it currently does not have 'live' scanning of files which means the user must manually perform a scan. Due to this limitation we typically have to recommend other packages for most of our end users.
AntiVir Workstation
Avast