What is a Virus?

A virus is a small piece of software coding that is usually piggybacked on to a legitimate program. There are 2 basic types of virus - Resident and Non Resident.

A simplified way of looking at these 2 types of viruses is that Non Resident viruses consist of 2 stages, in the first stage it finds new files to infect, then goes into the second stage to do the infecting. Resident viruses forego the first stage and loads the replication section into the memeory, ensuring that it is executed each time the operating system performs certain predetermined tasks. This method allows the virus to infect every suitable program fairly quickly.

This method causes more than enough damage if it attaches itself to something like a spreadsheet program as, each time you run the program, you also run the virus, giving the virus the opportunity to replicate, but if it attaches itself to the operating system, then replicates, the only answer may be to wipe everything from the disk and start again.

As you can imagine, the time spent by businesses in wiping a hard drive and reinstalling the operating system and/or all programs is time consuming, it can also mean the loss of critical data, causing major problems for any business.

This is why you need to create regular backups of your data, install a suitable antivirus and firewall and operate a strict policy on emails from unknown sources as most viruses enter the system on emails as an attachment.