Both spyware and viruses take advantage of loop holes un-discovered by Microsoft within Windows. Keeping your computer up to date with Windows updates is as important as keeping your antivirus software up to date. You can have the best antivirus software available (fully updated) but if your computer is behind on its windows updates it will still be very vulnerable to attack.
When Microsoft discover these loop holes they bring out updates to patch them up, these are distributed via Windows Updates. The best way to take advantage of these updates is to make sure you have automatic updates turned on.This means that your computer will automatically download any available updates in the background while you’re working; when you shut down your computer these updates will be installed. To turn on automatic updates go into the control panel, double click on the Security Center and then click on windows updates – you will be presented with a window where you can set your computer to update automatically when updates are available.