past programs

dear sirs

   I have a question .LOL

in 20 yrs or more  between Microsoft an Symantec  an other programs  ..We upgrade an replace with newer versions ,sometimes just deleting old programs ..Evan using program removal tools . Every time this is done , don't  the programs leave behind file fragments  that create  weak points /points of access  for hackers an/or  government  intrusion ......With fragments in overall operating system- does this cause computer slowdown an other malfunctions --I ask  because  after a year or so  my computer seams to slow down an malfunction causing me to go into registry  an clean an remove  fragment's  ....IS THERE A CLEANING PROGRAM IN YOUR TOOLS THAT WOULD DO THIS....I have used your Norton power eraser  this works great for what it is , but does not cover this case situation...