If you currently are not effected by any spyware or malware, I recommend using these applications and/or in the background.
If you are currently effected by any spyware or malware, I recommend using these applications to get rid of what you have. Why do you need to install all these? Not just one? Because each application has it’s own definitions, one scanner might pick up something another scanner would not or one scanner might have trouble getting rid of something whereas another one will not.
Make sure to check for updates after installing the applications so you have the latest updates to the definitions and what not else they application offers.
HiJackThis Disclaimer and Short Instructions This app you need to be careful with. Advanced users, with help by someone who knows this app or those of the understanding should only use this tool. When you run a scan with this, not everything what so ever is going to be bad. Removing everything would cause your system to crash most likely and be even worse. So if you do run a scan, I recommend copy and pasting that scan into the text box at this website to analysis your report and find which boxes to check off for removal from your system. You may contact me or at the forums for more help on this. The website is: http://hijackthis.de