I can change from AC power to battery without incident. When I change from battery power to AC power, Firefox flashes a few times then goes blank. To close the browser I click the "X", which luckily remains, and the "do you wish to close" box is blank also. I hit enter and Firefox closes. I reopen and select restore previous.... and I can continue. Just something I've never experienced, not sure how to fix it. Sometimes if I minimize the browser ("-") in upper right corner before plugging in my power supply, I can bypass this trouble. Sometimes it waits until I maximize the browser and it still flashes and goes blank anyway.