What are the best free and pro anti-spyware softwares ? How can they protect your pc from spyware ?

Anti spyware programs protect your pc from spyware , different users use different softwares , at times we may be confused of what software to use and what is the best one to protect pc from spyware.There were many , when my computer is hit by spyware , at that time , i didnt come to know about the software that i have to install , i was left in a confused state of which is the best anti-malware program that i have to use , when i gone through some of experts on spyware , they said me about Ad aware free from Lavasoft.This software is free to download and trusted by millions of users.
    Click here to go to the download page. Pro version also available.
    Click here to see the features of products pro , free and total security.

Screenshots :

Ad aware free internet security on work
Ad aware free internet security on work