My computer was loading up -sound problems etc lately. Sure enough -even with 2 firewalls - ISP's and min-- I had 18 spyware problems.
Some of the best spyware checkers are free.
http://www.safer-networking.org/
http://www.javacoolsoftware.com/spywareblaster.html
http://www.download.com/Ad-Aware-SE-Personal-Edition/3000-8022_4-10045910.html?part=dl-ad-aware&subj=dl&tag=top5
Be careful of hijackers who try to get you to buy their inferior or as good stuff instead of the free stuff. Happens often when searching. The above links should all be free.
I get a lot including both the serious and ignorable ones--rarely less than 20/day.
And still have to take out a lot of cookies by hand.
Google and refdesk both seem to be a source of a lot of them.
I first used the new Microsoft Anti-Spyware program and came up clean then Spybot found the 18 then I ran Ad-Aware and it found 6 more including a phone dialer that had been slipped in from somewhere. Fortunately I hardly ever have a dial up hooked up.