For anti-virus I use "AntiVir" by AVIRA:
http://www.free-av.com/
For Spyware I use Ad-Aware by Lavasoft for manual scans:
http://www.lavasoftusa.com/products/ad_aware_free.php
I also use Spybot: Search and Destroy for background spyware protection:
http://www.safer-networking.org/en/index.html