I have an Acer Aspire 4736 . had got it with Vista but then bought Win 7 Home and installed it. recently upgraded to Win 10 . while booting, it switches off itself almost 8 to 10 times . every time I have to manually power on again using the power button . it is connected to a TV via VGA cable all the time. I did recently a clean install of win 10 but the same. searched for windows 10 drivers in Acer website for this mode, but does not exist . thought to do a Win 7 install again with a bootable CD , but that did not work. so did a win 10 install with a bootable USB. But I am not sure if this is a OS problem or anything to do with HW or PSU .it keeps making a Hizzzzzz quiet for 1 sec and then again hizzzzzzzz sound almost always while the system is ON as if some access is always going on . its about 6 years OLD, battery replaced , keyboard replaced ( now I just use Wireless mouse n keyboard for access ). have a bootable Win 7 installation . Thinking of doing again a clean install and check , but really doubtful if this is a problem. can somebody give me some suggestions ?