got to go with OTHER. THE USER
spyware is only effective if you dont pay attention to your system, while installing apps.
first, make a backup of your registry files. keep em safe.
run a firewall - blocks (some) spyware from connecting back to server.
examine your ADD/REMOVE menu, look for something you didnt install. and remove it.
do a ctrl|alt|del, do you know what programs are running and what they are for? learn what you install and make sure something is not running you didnt install.
remove apps from loading via the MSconfig utility.
delete you cache daily, as well as cookies and the INDEX.dat file (only via DOS mode)
get a file shredder and dont delete files, shred them (overwrites clusters XX amount of times with 1's and 0's)
if you install an app that has spyware. just reboot to DOS, and replace the reg file with the backup copy.
backup your system before adding new apps. then if you get infected with spyware, restore to previous state.
if running a firewall. check the log, look for connections to services you arent running. if only running web browser. there should be no other ports being used, except for 53 -DNS, and your dhcp server.
look at spyware awareness sites, look at the listing of known offenders and dont download their apps.
you should not be solving the problem after the fact, you should prevent it beforehand. why install yet another app to fight another app. if ya didnt install the spyware app in the first place, you would have 2 less apps installed, running, eatting resources