It is very difficult to guarantee a 100% virus-free working environment. Apart from the requirement of knowing how to detect and handle viruses, followings are some guidelines on preventing viruses :
Despite anti-virus protection in place, it is a rule of thumb NOT to open email attachment unless you expect to receive it. There is always a possibility that the attachments might contain new virus that the anti-virus software is not able to detect it at all.
Avoid provide file shares to others.
Apply strong password policy if it is unavoidable. If you are using Windows XP, disable the simple file sharing.
Apply strong password to protect you machine. Do not leave administrator password blank or assigning trivial password with your Windows machine.
Avoid referring, storing or copying files (programs and documents) from unknown or untrusted source such as download from Internet or email attachments received from friends.
Consider to save a file in ASCII or RTF format when sharing your documents with others to reduce the risk of transmitting macro viruses.
Backup essential data files periodically.
