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I have a problem with my HP compaq 8510p laptop: when I start it, the fan starts and the power light is on, but the screen displays nothing. When I insert a bootable hard drive, it activates the hard drive light (meaning that the CD is recognized) but it stops after a few seconds. Same thing with any hard drive: the drive is recognized but does not boot.

What I've tried so far:

  • Changing the hard drive or booting with no hard drive (same problem)
  • Plugging anoher display via VGA : no display on the other screen
  • Inserting a windows-7 CD (same problem)
  • Booting only on battery, with battery and power cable, only with power cable (same problem)

So it looks like something is preventing the laptop from booting and displaying the boot menu. Do you have experienced something similar with a laptop ? What could be wrong ?

The laptop is out of warranty. The system used to be windows-7 x64.


Edit: I went to the help desk of my university. A guy took a look (he also tried to plug an external screen) and said that the computer is dead: on the HP laptops eventually the GPU card dies and so does the motherboard because they are linked. He saw this many times, and even if I can fix the problem, the laptop would crash again after a while. Do you have similar experience with HP laptops ? (mine is 4 years old)


Edit 2: Believe it or not, my laptop is magically working again. I have no clue about what is going on. Now it is like starting and old car: when you turn it on you secretly hope it will actually start... With that said, I expect my laptop to break again in the near future (its an HP after all) and I will accept an answer or add my own accordingly.


Edit 3: As expected, the laptop is down again. This time, sometimes when I power it up, it shuts down automatically after 3 seconds, sometimes not at all. In addition, when it does not shut down on its own, the power button does not work : the only way to shut it down is by unplugging the battery. As before, the screen is black, and only the power and battery lights are on. (the other ones: hard drive and wifi are off). I have tried to plug in another power plug, removing the battery and removing the hard drive without success. I might buy another laptop.

I've brought the laptop to a repair shop. The problem is indeed that the graphic card is down. It will be replaced by a new one.

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2 Answers 2

With the external monitor plugged in, try pressing Fn + F4 to actually switch to the external display. Just plugging it in might not be enough to get a picture on it, especially during boot-up. Might have to press the keys repeatedly to cycle through the different settings (internal only, internal+external, external only).

If that helps, then the problem is either the display panel or the cable. You can disassemble the laptop (service manual here) and check that the display cable is plugged in securely at both ends (motherboard and LCD panel) and that it hasn't been damaged anywhere (like where it passes through the display hinge).

Another thing to try is to shine a flashlight on the display panel and see if you can detect a faint picture on the display. It's possible that it's the backlight (or inverter) that has failed, which would render any image on the display too dark to see. The inverter is fairly easily and cheaply replaced, the backlight less so, and might even warrant a new display panel.

If none of the above work, then the problem is most likely with the graphics card. Fortunately for you, the guy at your university helpdesk isn't very knowledgeable, at least about your particular model. The HP 8510p uses an MXM slot for the graphics card, which means the card is replaceable. You can find used ATI HD2600 cards on eBay for $30-40 (make sure to get HP version, part # 454247-001). Might also be able to sidegrade to a Quadro FX570M (part # 455077-001), which is an option on the 8510w (workstation version of your laptop, same motherboard/BIOS).

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I tried to switch the display, and it doesn't help. I've also tried to remove the RAM and see if I have the beep from the motherboard, and I have no sound at all. So I think the problem is with the motherboard, not the grapic card, tough I am not sure. –  pinouchon Jun 19 '12 at 12:07
1  
@pinouchon As far as I know, HP laptops blink the Caps Lock or Num Lock LED, rather than beeping, for hardware errors. According to this document, it's 3 blinks for RAM, 4 blinks for the graphics card, and 5 blinks for the motherboard. –  Indrek Jun 19 '12 at 12:15
    
There is no blinking either. –  pinouchon Jun 19 '12 at 12:18
    
Thanks for your answer. I will try other motherboard/graphic card as I get back in my university where I can find spare ones (and update this thread accordingly). In the meantime, I am going to buy a new laptop. –  pinouchon Jun 19 '12 at 13:33

This sounds like ether the graphics card is broken, or the screen is broken and the graphics card does not use external screens on bootup. That your disk-drive is blinking usually only indicates activity, not a recognized disk. Did you have any symptoms before, like a flickering screen?

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I had no symptom at all. Everything worked fine. The problem occured after I put the computer on sleep. –  pinouchon Jun 19 '12 at 11:03

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