Hello,
There is a very useful page
here which tells you of spyware removal and free anti-virus software.
We would reccommend that you only have one anti-virus, as two conflicting ones can cause you a lot of trouble. Your should also have at least two spyware or adware removal programs.
Scan your system with each of these programs at least once a month, to ensure that you do not have excessive amounts of spyware.
Hope this helps,

Charles