Photos: How does spyware get on your PC?

The end user licensing agreement (Eula) can also be a giveaway and Chien warned that users should never take it for granted that there aren't nasty surprises lurking a long way down the terms and conditions.

GAIN features heavily in many tales of spyware woe, due to its association with the widely used Kazaa application.

Despite claiming it is an entirely legitimate organisation, GAIN and the associated Gator name are familiar thorns in the side of many anti-spyware advocates.

Chien said not only does the GAIN Eula state it will relay information back from the user's PC, it also states - in hope perhaps more than expectation - that users cannot remove the spyware from their PC or even encourage others to do. Other Eula's Chien has seen even include references to the fact the application may access and exploit user data held in Outlook address books and other critical applications.

Many spyware applications are programmed so as to be close to impossible to remove once installed, warned Chien.