I have a Compaq Presario CQ56 laptop that won't turn on. I've tried taking out the battery and unplugging it, holding the power button down for a minute then putting it back together again, but this does nothing. Any suggestions? Thanks.
This was one of the first threads I came to when I had this same problem (same model laptop). I spent a week reading threads/troubleshooting and no one had the answer. Geek Squad said it was the motherboard/cpu, just get another computer etc etc etc. Before you do that or spend a ridiculous amount of money try this. I hope it helps someone else:
It may be some type of a standby issue or a problem with the lid being out of place. My laptop went into standby mode and wouldn't come out. I still don't know why but it eventually turned on.
I left the laptop on (black screen, caps lock light blinking once every few seconds, power light on, f12 light on orange) for an hour + and closed the lid. I left the charger and battery in the whole time. It got very hot. I then turned it off and tried to turn it back on -- it came on.
Not sure if this would work for everyone, but it's worth a try before resorting to other measures. If you get it back on, take off standby mode and set the computer to not go into sleep mode when you close the lid. Keep the charger in. Basically, turn down the screen brightness/power settings and let it run all the time until you figure out what the root cause is. If your battery is old, get a new one that will hold power for longer if you have to travel.
(((( sending positive vibes out there so that your laptop turns on and you can get some work done!!! <3 ))))