Paul Wallbank from pcrescue.com.au is a regular guest on Tony Delroy's ABC radio programme and has spoken at length about spyware, browser hijackers etc.
You can use the following link to get a comprehensive summary of problems & solutions including links for downloading and updating free software such as Ad-aware and Spybot (and AVG Anti-virus and Zonealarm Firewall which I also use)
http://www.pcrescue.com.au/Protection%20kit.htm
BTW if you have a dial-up connection it would be a lot faster to get recent versions of these programmes from PC magazine CDs (they include them with most months' issues) and then get any updates over the net.