Trying to boot up my sons Compaq cq56-107sa
circa 2010
M/c (mobile computer?)The main battery is bad and shorted, remove it run on AC power pack, ONLY !the HP support site, no Fixya.shows the Long reset.battery out, power pack unplugged, push power button for 10 to 30 seconds, and release, this resets it.if pc latches up or goes to sleep or hibernate this resets it 3 ways , at least.leave the main battery out,there are many things that cause BSOD, black screens of *****, in your case, it's more drastic if battery out does not fix it.the PC for 7 years showed, "hit ESC to enter setup"in text on the screen for 7 long yearsif not today, then BIOS is dead, if that is dead there can be no windows.see?BIOS must work on demand or the screen is dead, or the PC has power issues,(power pack dead and more)so read page 77 here,http://h10032.www1.hp.com/ctg/Manual/c02657369Hammer esc after pushing power.hammer ESC, see BIOS wake up , and then hit f10that is boisthe first goal of any PC repair is that BIOS>then use a flash light.testsee page 93, see that CCLF tube, if dead the screen is dead even with a perfectly ok PC.see that.do the flash light trick http://www.pcdied.com/monitors.html#flashlighttestim replacing 2 , today, in one monitor that the tubes turned ugly yellow.the dont last 7 years, really\ much, rare to...the go yell, dim,blink madly or die.that at 20,000 hours use.(READ SHORT LIVED)The next year HP had LED back lamps. 2011. more