All computers should have some sort of malware protection installed on them.
The malware protection software must be kept up-to-date, this can usually be selected as an option within the software.
The malware protection should be configured to scan files automatically once they have been accessed. This will include downloading and opening files or accessing files on a removable storage device on a network.
The malware protection should alert and prevent connections being made to malicious websites when the user is accessing the internet.
All employees should be educated about the dangers and risks of malware.