Download and install one or more of the popular antivirus softwares and set them to update automatically. Viruses infest your computer from any of the input sources like diskettes, suspicious websites, emails and downloaded programs. Check these things every time you need to use them with these antivirus programs. You can also configure antivirus programs to automatically protect you whenever you connect to internet. If you are a professional user of internet, scan the whole system for virus as frequently as you want. These anti virus programs either destroy or quarantine viruses whenever they catch them.
Upgrade Your Operating System
Vendors of operating systems often upgrade their releases and distribute the upgrades as service packs or patches. The service packs plug loopholes in the operating systems and make them robust by taking care of bugs. Subscribe to continuous up-gradation programs which automatically download the patches as and when they are made available.
Treat Email Attachments with Due Diligence
Macros and viruses are distributed by their creators as email attachments too. Don't open the mail or download the attachment unless you are sure of the senders and you were expecting the mail. Suspicious mails and attachments could possibly contain self installing viruses. If the mail subject line sounds amazing or suspicious just delete it or scan the attachment prior to opening it.
Use Firewalls
Firewalls are by far the strongest internet/intranet protection for computer security. They are either hardware or software tools that effectively scan data transfers from and to your computer. You can set parameters to scan based on location and type of data transfer.
Password Protection
Use of stronger passwords is a great help in onsite computer security. Strong passwords are longer in length and combine alphanumeric combinations with upper and lower case alphabets thrown in. They are never the words from dictionary, names of places or humans etc.
Keep Backups of Important Data
Regularly make backups of important data, just in case.
Be sensible to check certificates when downloading something from an unknown site. Use file encryption facilities to curtail unauthorized access to your files. Finally, your office computer can be secured by password protection against manual intrusions.
