SECURITY

The following applications do an excellent job of cleaning up extraneous files, spyware, and viruses in Windows. These freeware versions do not
usually scan at user-defined times (the paid versions do). It is better to run them one at a time, preferably in the SAFE MODE, but I have not (yet)
encountered problems with running them concurrently overnight as an administrator and in the regular mode.  Before running them open them with
administrator priveleges and click on Update icons  (paid versions usually update automatically). Because automatic updates can interrupt what
you are doing I  recommend  that you deselect automatic updating where possible. Purifying an entire computer will typically take several hours
and I therefore run them simulataneously overnight . DO NOT INSTALL MORE THAN ONE ANTI-VIRUS PROGRAM - otherwise they will interfere
with one another and, at best, slow down detections.

REVO UNINSTALLER
Deletes detritus left over by sloppy or nefarious programming. I liked it so much I bought the paid version,

FOURMILAB PAGE ABOUT PRIVACY  (includes links to non-tracking apps)

AVAST ANTI-VIRUS 
Recommended , but disable either this anti-virus or Zone Alarm's. I use Avast.

CCLEANER
Cleans out unnecesary files, browser cookies, etc. Also the only reliable registry cleaner I have encountered. You should repeat executions
until nothing changes (MS Internet Explorer files are especially stubborn).

SPYBOT
Allows immunization against known spyware. In my experience it catches the most malware of any of the apps.
If you insist on just one malware removal app, this is the one.

SECURITY TANGO (Windows, Linux, Mac)
An orchestrated sequence of tasks to rid your computer of the most persistent malware. Print out the list of instructions
before using.