# Black screen with blinking cursor at boot time



## freegem (Jun 13, 2010)

Recently we had a problem with our monitor not getting a signal from the computer and it turned out not to be the monitors fault because we tried several different monitors and they all had the same problem with this computer. Once we determined that it was not the monitor causing the problem, my friend foolishly began to turn the computer on and off repeatedly because according to him the monitor would work sometimes when you first turned on the computer. When I say that he was turning it on and off repeatedly, I don't mean that he was properly shutting it down and rebooting it, I mean that he was forcing it to shut down over and over by holding the power button down while the computer was still booting up and then turning it back on to see if the monitor would come on. Now that he has done this, the computer simply boots to a blank black screen with a blinking cursor in the top left and the monitor still rarely works, so I just have no idea how to go about fixing this when the monitor displays absolutely nothing. Would a possible solution be to go ahead and reformat the hard drive? (we have been wanting to do this recently anyhow, I am just wondering if this is possible since we cannot tell the computer to boot from the CD and since we basically have no monitor or display of what the computer is doing). Or do you think that turning the computer on and off repeatedly like this could have possibly damaged the hard drive or another part of the computer? The computer has lots and lots of pictures of their children that they would like to salvage if at all possible so any help is very much appreciated. There is a text file attached with all the system details.


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## Tanis (May 30, 2006)

Turning the machine on and off like that will not do it any good at all, it could damage any number of components.

When you turn it on, do all the fans run and does the harddrive activity light flash, as it would if it was booting normally?

I would also check that all cables and connectors are securely in place, both in the case and connected externally.

Have you tried a different cable from the graphics card to the monitor?

What is the make and model of the machine, assuming it is a branded one like HP, Dell etc.? If not, what is the make and model of all the parts i.e. Motherboard, CPU, RAM, Power Supply etc.

Does it have an onboard graphics card and/or a removeable card? If you have both, try connecting the monitor to the other card.


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## freegem (Jun 13, 2010)

I did not check to see if the fans were all running or if the hard drive activity light was on, but I will do that as soon as I can tomorrow when I am with the computer again.

Everything inside and out is connected properly.

We tried multiple monitors each with it's own individual DVI or VGA cable, so it's not a problem with the monitor or its cable.

All of the system information is in a text file attachment in my original post. It's not a brand name it is a custom built machine and it is roughly 7 years old and not in great shape even when it works properly.

It does have on board graphics and we have tried connecting the monitor to the on board VGA port but the monitor still gets no signal. We have tried both the on board graphics and the pci express graphics but the problem persists.


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## Tanis (May 30, 2006)

Seems like you done the initial checks anyway, so we can (or rather you already have) ruled out a monitor or cable problem. As you have tried 2 graphics cards that would possibly indicate its not that at fault.

Unfortunately I can't check the text file due to my 'internet police' at work!

If the fans etc dont run, or just 'twitch' when you turn it on that would possibly indicate the power supply as died.
If all the fans run and you get activity on the hard drive, then the PSU is probably OK (for the time being at least).


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## freegem (Jun 13, 2010)

The hard drive light does not flash when I turn it on. I can't say for sure that the light worked before though to be honest. The computer has a second hard drive with no operating system on it, just a bunch of music and stuff. Could I just remove the hard drive that the computer is booting from and let it boot from the other hard drive and see if that one will work?


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## Tanis (May 30, 2006)

Unfortunately not, it won't boot to a harddrive that does not have an operating system (i.e. Windows) installed on it, you would just get an error saying 'Invalid System Disk'.

I take it all the fans in spin fully when you power it up then? If so, that would indicate to me that the power supply is probably OK.

Next thing to try is disconnect the hard drives, take out all add on cards, disconnect any CD/DVD drives, take out all but 1 stick of RAM (if you have more than one). Basically disconnect / remove everything apart from the CPU, 1 stick of RAM and the motherboard and see if it gets through POST (Power On Self Test) with the monitor connected to the onboard graphics card. It will still report an invalid system disk after POST.

Also, give motherboard a close visual inspection to see if you can see any sign of damage like for blown capacitors, electric damage / burns etc. They can be difficult to spot sometimes but if you find any that is a good sign that the motherboard is shot.

http://gallery.techarena.in/data/519/bad_cap.jpg

This picture will give you an idea what too look for, the leaking ones are fairly easy to see but ones with bulging tops are a little harder. Basically capacitors should be flat across the top, if they are rounded off that is likely a problem.

If you still get nothing from the above test I would probably lean toward the motherboard being faulty, although its difficult to guarantee that. As I said, turning it on and off quickly could cause no end of problems!


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## freegem (Jun 13, 2010)

I removed the hard drives, the video card and left only one stick of RAM in the computer. The monitor still does the same thing where it does not get a signal from the computer and it just acts like it's asleep. Is there anything else I can try to narrow down the culprits? If I can get the computer to atleast display something on the monitor I will consider this a victory, but even if it starts working there is still the problem of the black screen at boot time!


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## freegem (Jun 13, 2010)

When I did the above test I had the motherboard, the CPU, 1 stick of RAM, the CD drive and my modem card all connected. Trying to boot the computer this way gave me the same problem with the monitor not coming on, but then I removed the modem card and the CD drive and now the computer is booting normally and the monitor is working again. All I did was remove the modem card and CD drive and all of a sudden it's working? What could this mean? Eeveryone was telling me my motherboard was faulty but now it seems to be working fine, please help!!! I had already picked out a new motherboard + CPU + RAM and now I'm skeptical about buying any of it because I'm not sure if it'll fix my problem.

Edit: We have had this problem happen both while the video card is out of the computer and also while it is in the computer. Does this rule out the possibility of the graphics card being faulty?


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## managed (May 24, 2003)

Well it looks like the CD drive or the Modem card is to blame, re-connect one of them to find out which it is.

Chances are the Motherboard Cpu and Ram are fine. I certainly wouldn't buy anything yet.


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## freegem (Jun 13, 2010)

We did remove both the cd drive and the modem and we tested them both individually and the computer worked fine. Then we reinstalled the graphics card and the problem started again. Then we took the graphics card back out and now the computer is working again. So now the problem has happened both with and without the graphics card. It has also happened both with and without the modem. It has also happened both with and without the CD drive. I has also happened both with and without the hard drive. What on earth!!! Any ideas?


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## Tanis (May 30, 2006)

Sorry for disappearing for a while, had to go away on business at short notice.

I have just read through your posts and at the point managed posted I would of said the same as him, that it would appear to be the CD and/or modem card that were causing the problem.

However, as you have posted afterwards that you have had the problem with and without various bits of hardware installed, then I would possibly lean toward the motherboard, CPU and/or RAM as they appear to be the only common factors.

So, just to check 

You have tested with only CPU, 1 stick of RAM and the onboard graphics, nothing else and the problem doesn't occur, i.e. it boots OK? (If you have more than 1 stick of RAM, have you tried the above tests with another stick installed?).

If you put any other part in (just 1 part) the screen will go blank on boot up?

Have you tried resetting the CMOS / BIOS back to defaults via a motherboard jumper? There should be instructions on doing that either on the boards website or in the manual.

If it is as I've interpretted it above, then I would possibly lean toward the motherboard being at fault, as the problem seems to happen as soon as you connect anything to it (apart from CPU, RAM).


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## freegem (Jun 13, 2010)

Oddly enough I found a random post by googling some key words for my problem. The post said that the solution to this problem is to unplug the computers power cord and hold the power button for 30-60 seconds, then turn the computer back on. Obviously I laughed at this at first glance, but then I tried it since nothing else was working and I'll be damned if it didn't fix my problem! Has anyone ever heard of this solution? How on earth did this fix whatever was wrong? There were loads of other people who claimed that this solution also worked for them when they had my same problem. Anyone know the reasoning behind this seemingly silly solution?


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## Tanis (May 30, 2006)

Glad you got it sorted, ill remember that in the future.

No idea why that would work unless there was a capacitor discharge problem somewhere and that reset it. I would imagine that process would only discharge any power stored in any of the capacitors, but I could be wrong.


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