The  Program Spyware Doctor from PC Tools, and also Spyware Catcher from Tenebril! Install and run both at all times and they will get what each other misses. Add Threat Fire from PC tools to monitor system activity and root kits( also stop them) and viruses and also add the Spyware doctor anti -Virus and your completely covered. 

I run all the free versions of these software's on my computer for years now and they don't slow it down one bit. I've done every combination in the book and tried everyone out there. This is the combo that works the best for me! It will probably do so for you also! You need to go to the bottom of this page and click on Google pack for the free Spyware Doctor from PC Tools to find the free version.

Yes you can run all free versions on your PC if your in a cash bind and have enough system memory or a newer computer but for ease of use and speed! Its easier and doesn't take as much memory or slow your computer down as much if you buy these programs sport these vendors and not use the free programs. But if you want to test my opinion on what's best I suggest you try all the free programs and then buy the simpler to use more comprehensive package programs!