Why Do Multiple Identical Windows Pop Up When I Open Explorer?by LarryP
Double-clicking on Explorer should in theory bring up just the one window you expect. There could be an issue where you get multiple identical windows popping up, however, and settings and processor lag are two of the possible culprits.
There is a setting in which the icons that you click are activated upon a single click as opposed to a double click. If this setting is selected and you are double-clicking, it will bring up at least two instances of Explorer. This setting is generally found under "Mouse" in "Control Panel."
If your processor is slow, you will experience some lag before Explorer comes up after you have tried opening it. This might cause you to believe you haven't double-clicked properly or missed the icon and try opening it again. Depending on how slow the processor is, you may activate several Explorers before they start opening.
Your mouse may not be working properly. If you have ruled out all other options, use another mouse on the computer. If the new mouse can open Explorer fine, then you will know that the other is faulty and needs to be replaced.