Also see Note 4 and Note 5 

Finally, if you are still not sure about whether to get rid of your existing security software in favour of the programs listed here then ask yourself "Why are you here reading this page"?  It surely must be because you have a sick windows computer.  If that is the case then one must assume that your existing security and maintenance software is not doing what it is supposed to do.  Even if you paid for a security program and the license is still valid, my advice is to start again from scratch, clear everything out and follow ALL recommendations in the 28 steps of this procedure.