How clean is YOUR computer? pt 2

Now most of you reading would have read my article computer hygene. Now that was the physical aspect of computers. Today, we'll move onto the software component.
Recently, there appears to have been a surge in viruses, trojans, spyware, or whatever you like to call them.
To make things easier to understand, I call them annoying things that screw around with your computer.

Take the following for example.

3721 infections...and you still expect your computer to run fine??

From Misc

More often than not, people do not realise that their computers have already long been infected by these bugs, and when they finally do realise, its only because their systems have been so badly damaged that they can no longer use it.
So when was the last time you've scanned your computer???