Random window keeps popping up.

Facebook window keeps popping up.

The title on the window is "Facebook Password". The message inside the window says "Enter the password for (my email) in System Preferences."

There are 2 options to click - Preferences and Cancel. Clicking Preferences and /or clicking Cancel only closes the box for a second or two before it pops back up again.

I have tried several suggestions from the older responses here to no avail. Any suggestions on how to fix this?

Thanks ~ Jackie