Computer Hope

Hardware => Hardware => Topic started by: arcooke on September 23, 2007, 01:37:17 PM

Title: Computer turns on, no beeps, no display.
Post by: arcooke on September 23, 2007, 01:37:17 PM
My mother has an HP desktop computer.. it's not terribly old.  Maybe 3.5 years or so.  It's completely stock, no mods, no tweaks, no third party components, etc.

Here's the important part:  Over the past month or two, she's been having occasional, intermittent problems with what originally seemed like the monitor pooping out.  What was happening is that she'd be in the middle of doing something (email, graphics, whatever.. but nothing graphic intensive), and all the sudden her screen would seem to shut off for a split second, then come back on.  Then yesterday, her system completely locked up... mouse just stopped moving and she had to do a hard reboot.  Another thing that has been happening, is that occasionally one of the fans inside the computer (I'm guessing the CPU fan) would start going faster, as if the CPU was getting too hot.  These 2 problems seemed to happen separately though, no direct connection between the two.

Here's what's happening:  She turned her computer on today and it wouldn't boot up.  No video, no beeps.  The system just turns on, fans start spinning, and that's it.  I opened the case and felt the heatsink and it IS warm.

Any guesses on what sounds most likely to be the problem?  I'm guessing either the CPU, motherboard, or video card, but if it was the video card, you could at least expect a beep I'd think.

Thanks
Title: Re: Computer turns on, no beeps, no display.
Post by: 2k_dummy on September 23, 2007, 01:48:23 PM
My guess is faulty ram.
Title: Re: Computer turns on, no beeps, no display.
Post by: arcooke on September 23, 2007, 02:19:55 PM
I just got done replacing the video card and the ram.. I tried 2 sticks of good ram and a video card that I know works.

So, it could be:
Ram
Video Card
Motherboard
CPU
PSU

I'm leaning toward CPU, but I don't have extra parts to test with. :\
Title: Re: Computer turns on, no beeps, no display.
Post by: patio on September 23, 2007, 03:04:35 PM
How did you eliminate the possibility of the vid card and the RAM ? ?
Was the RAM tested ? ?
What vid card did you throw in there ? ?
Title: Re: Computer turns on, no beeps, no display.
Post by: arcooke on September 23, 2007, 03:13:27 PM
I had spare parts from my computer before I upgraded.  Her computer has an AGP GeForce 6200, I also had the same card.  Only difference was that hers was like an LE edition and mine was not.

I also had several sticks of DDR400 that I was able to test too.. both were pulled from a working system, and tested in hers (also using DDR400).  Still no beeps.. no change whatsoever.
Title: Re: Computer turns on, no beeps, no display.
Post by: Fed on September 23, 2007, 03:21:21 PM
Disconnect the computer from the wall socket, wait 30 seconds reconnect and give it a try.
Title: Re: Computer turns on, no beeps, no display.
Post by: patio on September 23, 2007, 04:40:44 PM
You didn't answer the questions...
How did you test the RAM..."it worked in another machine" doesn't qualify...
How do you know the vid card is good ? ? again see above.
Title: Re: Computer turns on, no beeps, no display.
Post by: arcooke on September 23, 2007, 07:11:16 PM
@Fed
I have tried that numerous times with no success.  Thanks.

@patio
I don't know what else you want me to say.. the ram and video card were pulled from a machine in perfectly good working order (minus a hard drive) and tested in the problem PC.  The symptoms did not change, still no beeps, still no video.  To me, when RAM works in one machine, and doesn't work in the problem machine, the problem is not with the RAM.  The same thing for the video card.  I can't test either of the parts any other way, as my only other fully-functional machine uses PCI-e video and DDR2 RAM.  Did I use memtest?  No, and I can't.  The spare machine is missing a hard drive.. I don't have any spare IDE drives.  If that's what you were asking, you could have just said it.  Otherwise I don't know what it is you're asking me.

I'm not a computer idiot, but I don't have sufficient spare parts to individually diagnose each piece of hardware to figure out what the problem is.  Hence why I came here and asked if anyone might know, based on the symptoms, what the problem sounds most likely to be.
Title: Re: Computer turns on, no beeps, no display.
Post by: Fed on September 23, 2007, 07:23:22 PM
I assume you can't test the RAM because nothing shows on the screen?
My money is on a faulty PSU at this stage, have you got one to swap it with?
Title: Re: Computer turns on, no beeps, no display.
Post by: Mastodont on September 24, 2007, 03:14:39 PM
The spare computer doesn't have to hve an HDD to run memtest - You just need to make a bootable diskette or CD and boot from it.
Title: Re: Computer turns on, no beeps, no display.
Post by: deep on September 24, 2007, 03:45:33 PM
Are you able to get to the bios?  It could be the monitor or its the board.  IF the fan is spinning there is power so its not the power supply. 
Title: Re: Computer turns on, no beeps, no display.
Post by: Fed on September 24, 2007, 04:19:56 PM
Quote
This is the cause of numerous PC problems where lights and fans are operating but it won't boot. This occurs because the power good signal is not received.

When the power supply first starts up, it takes some time for the components to get "up to speed" and start generating the proper DC voltages that the computer needs to operate. Before this time, if the computer were allowed to try to boot up, strange results could occur since the power might not be at the right voltage. It can take a half-second or longer for the power to stabilize, and this is an eternity to a processor that can run half a billion instructions per second! To prevent the computer from starting up prematurely, the power supply puts out a signal to the motherboard called "Power Good" (or "PowerGood", or "Power OK", or "PWR OK" and so on) after it completes its internal tests and determines that the power is ready for use. Until this signal is sent, the motherboard will refuse to start up the computer.

In addition, the power supply will turn off the Power Good signal if a power surge or glitch causes it to malfunction. It will then turn the signal back on when the power is OK again, which will reset the computer. If you've ever had a brownout where the lights flicker off for a split-second and the computer seems to keep running but resets itself, that's probably what happened. Sometimes a power supply may shut down and seem "blown" after a power problem but will reset itself if the power is turned off for 15 seconds and then turned back on.
http://forums.whirlpool.net.au/index.cfm?a=wiki&tag=power_good_signal