According to the tech folks at Microsoft, one in every twenty Windows based computers is infected. These infections are capable of disabling anti-virus programs and also turning off Windows update features. This in turn prevents the user from removing the virus and the nasty bugs continue to infect other users.
But are these statistics reliable or are they just a scare tactic by Microsoft? It all depends on which side of the fence you sit on. The pro-Microsoft folks will have an opinion that Microsoft is trying to get people to clean up their computers. The anti-Microsoft crowd will have the opinion that Microsoft statistics are flawed, since the 95% of those that had a clean PC may have thought they were infected.
Here is my personal opinion. Those folks who have an infected computer have no clue they even are infected. These same folks are the ones that use their computer as a toy and are clueless about infections or even where to go to get their systems cleaned. These same clueless folks will continue to use their systems until it completely stops on them or when they no longer can connect to Facebook.
In my opinion the Safety Scanner will not be used by those most likely have a non-infected computer. I also believe that 5% is a rather low number of infected Windows computers. I think the number is higher.
By scrubbing your system clean, you will have a more enjoyable computer experience.