Starting yesterday, whenever I open Firefox, a second page also opens. It is blank and unresponsive to commands. Doesn't do much of anything. The address in the address bar is for a crypto-currency exchange which I've never done business with nor ever visited to my knowledge. No input either on the main screen nor in the address window seems possible. The only thing functional on the page is the red-X in the upper right hand corner. It works fine. But whenever I close Firefox then re-open it, the second crypto-exchange page is there again. It opens concurrently with the regular Firefox browser page. Which functions normally. I don't know what to make of it, and I don't want it. Does anyone have any ideas???