Spyware was first noted in 1995 and publicly used in the news around 2000 in an attempt to sell firewalls.*

Several programs check for spyware and I have found that sometimes you have to run more then one program to get rid of some really bad spayware programs. Most of the antivirus programs also provide spyware checking but i have found this not to be very effective. I personally use Malwarebytes and run it once a week.

Spybot
Malwarebytes