My computer mouse is “dragging”, ie. won’t track properly. I cleaned out some dead files, cleaned the mouse mat. My HD does not need defragmenting, and scandisk says there are no errors. Everything else appears in order. What might be the cause?

If it is just a problem of the mouse not tracking properly then we can safely assume that it is a hardware problem with the mouse, and not a software (eg. drivers) problem. Your problem is commonly caused when there is dust in the mouse which interferes with the internal moving parts of the mouse. This can be easily fixed by taking out the mouse ball and giving it a good clean (with a tissue, cloth, etc’¦). If this does not solve the problem, then it is being caused by dust inside the mouse. In this instance, I suggest that you remove the cover of the mouse and get rid of any dust that has accumulated inside the mouse over the years.