There are numerous ways that a computer can become infected with a virus. There are also many variants of a virus that may harm and even damage your valuable data, or simply make your computer behave in a way that is very unproductive.
How does your computer get infected with a virus?
One of the most common causes of a computer infections is that the user confirms dialog boxes that pop up without reading and understanding what confirming the pop up will do.
TIP: Whilst browsing the internet, make sure that if you click to confirm the popup or dialog boxes that you fully understand the contents and actions of what you are authorising the computer to do.
TIP: When installing or updating software, ensure that you are only installing what you need. Read carefully especially check boxes to ensure that 3rd party software will not be installed also.
Another very common vehicle of infection is opening email attachments, even from as it appears a trusted source such as a friend or relative.
TIP: When opening emails, especially with an attachment, if the email was not expected or was received from someone unknown - be careful when opening it.
Not updating Windows (or other operating systems) or other installed software.
TIP: Ensure that Windows is always up to date. Make sure that critical updates are installed automatically and periodically check for other published updates. Ensure all other software is kept up to date including browser plugins.
Downloading for free copyrighted material (Pirating)
TIP: Much paid content that is provided free can contain all sorts of nasties - viruses, spyware, malware. Alot of nasties also come down via sites containing pornography.
Running a computer without any antivirus protection.
TIP: Ensure that you have installed an up to date a reputable antivirus software package.
Downloading infected software.
TIP: When downloading software from the internet, ensure you are downloading software from a reliable source.
How do I know if I have a virus or other threat?
Popup windows that encourage you to visit strange sites or advising that you have a virus and to download a scanner
Your internet home pages suddenly changes
Your friends ringing you up asking about strange emails you have been sending them
Your computer starts crashing repeatedly or your computer starts becoming slow and unresponsive