I've had Windows Essentials for more than 2 years and it has never found even one item on my computer. I recently downloaded Malwarebytes just as a cross check. The first time I ran malwarebytes it found over 400 items. Three weeks later I ran it again and it found 16 items. Windows essentials still has found none. WHY??

I should add that twice I've had to have a computer guru clean viruses from this computer. Why doesn't Windows Essentials find anything?