# Getting "no signal" from a computer that worked fine last boot



## tomzx (Jan 14, 2005)

I have this weird problem since 2 days, I have no idea when it started though.

Here's my actual problem: if I restart my computer, the monitor will not get a signal from the video card and will display "no signal or cable disconnected" even though it's connected. It didn't do that to me in the past. If I power off the computer (on/off switch at the back) in order to shut down the motherboard bios or whatever is in the mobo, restart the computer without the video card on shut it down again and plug it back, I get it working again, but as soon as I restart the computer, no more signal.

I'd like to know if this is related to the bios in some way and if there's any way to fix it. I believe there's no actual problem with nor the graphic card or the motherboard because I can get it to work each time I do the previous "method".

System settings:
CPU: AMD Athlon 64 3000+
Motherboard: Asus K8V-X
Sound Card: On-board
Monitor: AOC Spectrum 7Glr
Operating System: Microsoft Windows XP Pro


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## kiwiguy (Aug 17, 2003)

It's highly unusual for a BIOS problem to cause that.

The "no signal" message comes from the monitor itself, telling you the PC has not booted.

That could be due to the video card, the motherboard or the power supply.

Removing and refitting the video card curing it is "odd", but I do wonder if it actually is a failing power supply unit that is exhibiting the effect.


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## tomzx (Jan 14, 2005)

kiwiguy said:


> Removing and refitting the video card curing it is "odd", but I do wonder if it actually is a failing power supply unit that is exhibiting the effect.


But how would you explain the fact that it's working after I do these manipulations? How can you say that it's a failing power supply. If it was failing, it would work from times to time, but this "technique" works EVERYTIME...


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## kiwiguy (Aug 17, 2003)

But as we don't know the exact steps you take, we can only make some assumptions.

Some PSU faults are only reset when power is physically removed from the PSU for a minimum time, and we don't yet know if your card uninstall/reinstall process is the only one you have tried that actually accomplishes that?

Even when "Off", the PSU continues to supply some parts of the motherboard. Only when Off on the switch at the wall, or unplugged, or switched Off at the back of the PSU (if a switch is fitted) is it truly "reset".

And let's be crystal clear here, I am not "saying that it's a failing PSU" as you state. 
I am "wondering" if it is.


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## tomzx (Jan 14, 2005)

Well here's a "crystal clear" list of the exact step I take:
1. Shut down the computer + power supply turned off (switch at the back of the computer ON the power supply)
2. Remove the video card + cable from monitor to video card
3. Power supply turned on (auto boot of the computer)
4. I press the front power button until it shut down
5. Power supply turned off
6. Reinstall the video card + the cable from monitor to video card
7. Power supply turned on (auto boot of the computer) but this time the video card works.

I would say I have a hard time believing it's an hardware failure because it does work with this method, so it would be mostly software or programmation making it not send the signal to the monitor, but I believe there's a reason behind the fact that using this method gets it working once more.


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## dastumster (Sep 11, 2006)

I would remove the video card, and insert it into a different slot.


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## squidboy (Dec 29, 2004)

Just to add my 2 coppers:

You need to separate this issue from the hardware and the software.

If, as per your 'fix', you see some initial video card/bios bootup messages, but then get the no signal message, this points to software (Windows).

If, as per your 'fix' you see nothing and immediately on power up you get the no signal message, this points to hardware. Either your monitor, video card, mb/bios, etc.


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## tomzx (Jan 14, 2005)

Squidboy: I see nothing immediately after the power up. I receive no audio beeping but I'm currently wondering if my pc speaker is set up correctly (the one that beeps at startup).

dastumster: that would be hard (let say impossible), it's a agp card, and I'm over a 1 agp 8x slot mobo.


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## Bob Cerelli (Nov 3, 2002)

When it works, do you ever get a beep just before it starts to boot?


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## tomzx (Jan 14, 2005)

Bob Cerelli said:


> When it works, do you ever get a beep just before it starts to boot?


Nope.


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## tomzx (Jan 14, 2005)

Someone on another board said it was possibly the north bridge that fried. But once again, if something was fried, wouldn't it simply not work anymore?

If no one has any other propositions I believe I'll have to reset my CMOS.


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## tomzx (Jan 14, 2005)

Latest news: I've just shut down my computer using the power supply button and restart it and doing so WILL get the graphic card to be taken into consideration. Any new thing to consider?


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## squidboy (Dec 29, 2004)

tomzx said:


> Latest news: I've just shut down my computer using the power supply button and restart it and doing so WILL get the graphic card to be taken into consideration. Any new thing to consider?


Interesting. I'm speculating a short somewhere. That's my guess. The only sure-fire way I know to troubleshoot this is to pull it out of the case and place the motherboard on some non-conductive material (like a nice piece of cardboard), then attach only what you need to boot and run:

power supply
motherboard
cpu
ram
video card
hard drive

The only other time I ran into this issue beyond that was a failing motherboard due to blown capacitors which would be visibly bulging or leaking.

EDIT: forgot to add, if you take the cardboard route, theres a jumper where you attached a lead from your case to start up. Simply short it (touch both) with a screwdriver to initiate power and boot up. This is safe if done correctly and necessary to troubleshoot. Ask if you need further details...good luck.


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## tomzx (Jan 14, 2005)

I've removed my ATI RADEON 9600 from the agp slot and replaced it with a GeForce 256 and it works every boot... I also tried with a ATI RADEON 9200 SE (pci) but this time with no success. Possibilities that there are some compatibility problem?

I've seen the problem of ATI card being problematic when installed on computers, I guess there's a possibility (might also be that there isn't enough current as well, who knows).

Any idea on what it could be?


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## CitrusLime (Jun 19, 2007)

I had exactly the same happen to my Pc and it turned out that it wasn't the graphics card or RAM etc but that the CPU had overclocked itself. This happened 6months after I bought it.The technician had to flash the BIOS chip and it was as good as new.


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