A large amount of very useful free software is available either as Open Source of Freeware. If you are a business user, please check the licensing conditions carefully.
The free versions of AVG and Avira are both excellent options for
home users. Note that these versions cannot be used by businesses.
For business use we recommend Sophos - please contact us for details.
If you are using Windows Vista or Windows 7, the built in firewall
probably provide sufficient protection, particularly if you are using
a router firewall (which you should be). On Windows XP we would
recommend that you use a third party software firewall. The free
version of Zone Alarm is a good option for
home users. Note that this version cannot be used by businesses.
Open Office provides an excellent alternative to Microsoft Office
and is free for home and business use.