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Old 01-25-2006, 05:10 AM
bluecanary bluecanary is offline
Join Date: Aug 2000
Location: London, England
Posts: 1,528
What's wrong with my computer (monitor won't come on)?

My home desktop computer is not working properly. The monitor won't come on when it boots up. I know the computer itself is booting up normally because the Windows startup and shutdown sounds play, as does the ping noise when I put in my pen drive.

The problem manifested itself sometimes before (on Sunday and Monday) as display corruption (such as a pink square somewhere on the screen). About two minutes after this appeared the display would go off altogether and I would have to restart. But now I cannot even get that far.

My initial suspicion is that there is a problem with the cable between the monitor and the graphics card. Unfortunately the cable is housed within the monitor at one end so it's not as easy as just swapping the cables out to test this. It could be the graphics card, but then why would the computer boot up normally?
Old 01-25-2006, 06:04 AM is offline
Join Date: Mar 2003
Location: Minneapolis, MN
Posts: 13,785
Easiest way to test this is to do one or both of the following:

- carry your monitor over to a friends' who has a similar computer, plug it in in place of his monitor, and see if it works there. If yes, your monitor is OK, it's your video board that's gone bad.

- borrow a similar monitor from a friend, carry it home and plug it into your computer, and see if it works. If yes, your computer & video board are OK, it's either your monitor or cable that's bad.
Old 01-25-2006, 06:15 AM
GuanoLad GuanoLad is offline
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Join Date: Sep 1999
Location: Where the wild roses grow
Posts: 23,694
If there's a problem with the video card, the computer will not boot up.

As you say it does boot up properly, then it is almost certainly the monitor itself. It's buggered. You need a new one.

It may, however, be the cable. Swap that with another if you can.
Old 01-25-2006, 07:01 AM
Nanoda Nanoda is offline
Join Date: Apr 2002
Location: Edmonton
Posts: 3,835
If it's an LCD monitor you've got, I'd be willing to entertain the "broken monitor" theory. If not, it's almost certainly your video card. When you push the contrast/brightness adjust controls, does the on-screen-display appear? If so, the monitor should be fine.

A broken VGA cable would be indicated by the screen uniformly changing colour, as either the red, green or blue signals are lost. (Not sure about broken DVI cables). Failing LCDs are usually indicated by lines, but possibly squares, but the most likely explanation is that your video card is hooped, as that can definately result in screen corruption.

As for booting, that's perfectly plausible depending on how it failed. I had a GeForce MX440 fail over the course of a month, first displaying pink pixels randomly over the screen, increasing to corrupted displays when in 3D mode, and eventually either displaying nothing or refusing to boot.

If your video card is an add-in, you can obtain a replacement anywhere. If it's of the on-board type, I'd worry about future failure of the motherboard, but would probably toss in an AGP card and disable the on-board card anyway.
Old 01-25-2006, 09:29 AM
Mindfield Mindfield is offline
Join Date: Dec 2005
Location: Overworked
Posts: 6,125
Originally Posted by GuanoLad
If there's a problem with the video card, the computer will not boot up.
Not necessarily. This is only true if the motherboard's self-diagnostic fails to detect a current from the PCI/AGP/PCI-E slot, indicating that either no video card is present, or the one that's there isn't powering up. It is not able to determine whether or not the card is working properly if it's still powering up. In these circumstances the machine will continue to boot as if nothing is wrong.

Given that the OP originally experienced visual corruption on the screen I would say it's almost definitely a dead video card. If it was a problem with the monitor itself if would generally affect the entire display -- squished screen, inability to display red, green and/or blue (assuming a CRT monitor here), inability to sync properly with video signal (most digital monitors will display a black screen and possibly a "NO SIGNAL" message on the screen or sumsuch), etc. A damaged cord will often result in the latter two symptoms as well. I have never seen nor heard of a monitor/cable problem manifesting as a single discoloured patch of screen however; to discolour one square area on the monitor would require that the guns still be working perfectly and displaying colour normally except otherwise in that one area (which strikes me as impossible simply due to the nature of how CRTs work)

Video card death on the other hand can and often does manifest as video corruption -- dots on the screen, discoloured lines or patches or things of that nature. Often the visual corruption is partially symmetrical, and it's usually static (unmoving, consistent, possibly progressive pattern). This is a sure sign that the RAM on the video card is going bad. This will eventually progress to no video signal at all.
Old 01-26-2006, 04:31 AM
bluecanary bluecanary is offline
Join Date: Aug 2000
Location: London, England
Posts: 1,528
I haven't had the chance to try anyone else's monitor, but it came on when I tried booting it up last night so I tried an experiment by pulling out the monitor cord slowly from the computer end to see what effect it would have on the display. The effect it had wasn't anything like the original problem.

I could do this for a five minutes after it booted up, then the corruption appeared and it went off, and wouldn't work again after that.

My monitor is an "old-fashioned" CRT monitor not a digital/LCD one. The graphics card is a separate card to the motherboard. I am now quite convinced that the problem is indeed with the graphics card - this is good because these are cheaper to replace and lighter to carry home from the shop!


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