Yes but I'd also recommend a triple pronged approach to getting rid of / protecting yourself from spyware / adware that causes ill system effects that antivirus software doesn't pick up on. Use Adaware, Spybot S&D and Spyware Blaster - again, all freeware programs available from snapfiles.
Most people may think this is OTT but in my opinion it is not, I use this approach to look after hundreds of machines I look after in Midlothian, Scotland with the exception we pay for Sophos Antivirus as it's generally accepted as the best. If you don't use this approach, especially in my job where kids are involved and visiting games websites and mp3 sites, you end up with undesireables such as 180search assistant, web rebates, shop at home select agent, toptext i lookup and eZula causing all kinds of system problems.
HTH,
Brian.