My Uncle bought me his Compaq Presario CQ62. The power came on. The caps lock light came on as well as the wifi light (on the F12 key). But a black screen on startup. I first assumed that his screen was gone. When he gave it to me to check out, the first I did was hook it up to an external monitor. That wasn't the problem.
The fan was running but it didn't sound like it was booting up. I removed the memory chips and turned it on. This should have caused the system to beep continuously. But nothing. Tried a few suggestions found online but nothing. One YouTuber suggests that it's a video card issue and I was supposed to dissect the computer, remove the motherboard, heat up the video card to about 200°C. I don't really have the resources to do that. Searching online produced no workable results except for a curious comment on a YouTube video.
The video that you can watch here: Compaq Presario CQ62 - How to fix black screen problem
One of the comments suggested a strange fix and I decided to give it a try.
Warning: I only recommend this procedure for data recovery. For information only. Use at your own discretion.
Came across a bit of an extreme method that I only recommended for data recovery. That involved sticking a screwdriver in the vent to the heat sink fan to stop it from running. You can also just tape up the vents. Turn on the laptop and let run until it shuts down from overheating and then unplug it, plug in again and then turn on. Yes, defy all logic by overheating a laptop to start it up. Amazingly it works. I got it running and I kept it going for a full day. Hoping that something would hold when I turned off. It didn't.
Other troubleshooting tips found online with no success. Those include:
My Uncle at this point decided to buy another computer. So this one became mine. I'm where old tech comes in it's final moments. :-) I either get it working and continue to use it or dissect it for it's parts. I decided to dissect this one.
I hate these older models. The ones with a billion and one screws and almost microscopic cables. But now that I have it stripped down and removed the motherboard I decided to give restoring it one more shot.
I removed the Fan Heat Sink Assembly and cleaned of the old thermal paste on the CPU and GPU, reattached the fan/heat sink, and wondered, how hard it would be to put this thing back together.
Some research online suggested it was a CMOS/BIOS issue so I also replaced the CMOS battery. Had a few spares but I don't know if any are good. Put one in anyway and continued to reassemble the laptop.
After, I tried turning it on again but with the same results. On a hunch I tried the holding down the power button thing again and this time it worked. Turned it off and then on, gone again. Tried it a second time. Working again. Turned it off. When I turned it on again it booted up and it's still working.
So the only thing to do now is to mothball this thing until some future time when it might come in handy. Might remove the hard drive and use it for backup purposes.
Other resources:
COMPAQ CQ62 take apart video, disassemble, how to open disassembly
How to disassemble HP G62 or Compaq Presario CQ62
Disassemble a HP Notebook – 15-bs023ca - Changing A Hard Drive In HP Notebook 15