Hi, I have a problem with my 18 month old laptop, F505ZA; for some reason both my original charger and my back-up multi-fit charger overheat when I try to charge my laptop. I did some research and found a post that suggested it was a battery problem, however, I have installed a new battery and I am still getting the same problem. The charger overheats and the battery doesn't charge. Has anyone else had this problem or know how to fix it please?