Monitor Says “No Signal Input” or “Monitor Going to Sleep”
August 5th, 2011 
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(Free Members Only) Have you ever had a problem with your computer when you turned it on, that the monitor stayed dark just as if it were still off, or if it displayed anything at all, it said “No Signal Input” or “Monitor Going to Sleep”? Or in some cases, along with a dark screen, did your computer immediately start making any beeping sounds?
The “No Signal” or “Monitor Going to Sleep” display on your monitor is actually generated internally within the monitor, and aside from a connection problem, the monitor is probably okay. This typically occurs when the computer has failed in a way that there is no video output signal to the monitor. As for any beeping, it is sort of a morse code indication about a Power-On Self Test (P.O.S.T.) that failed. While this article was written with desktop computers in mind, most of it still applies to laptops as well, just know that laptop parts are layed-out differently, and may not be user-accessible.
You probably noticed that when your computer is working, that you hear a single beep when your computer begins to boot-up. This is a good POST beep and means that your system passed POST. If your computer didn’t pass POST and it beeps with continuous combinations of long and short beeps, there are 5 main hardware items that can cause this problem:
- Memory or Ram (most likely reason, 1 or more ram modules may be loose or bad)
- Motherboard (somewhat likely if you have integrated video, and very likely if you have any bulged capacitors)
- Video Card (somewhat likely, especially if the fan failed)
- CPU (unlikely unless you had a failed CPU Fan, and AMD CPUs fail more often than Intel CPUs)
- Power Supply (most unlikely, especially if the computer turns on, but older low wattage power supplies that still power-on may not be able to handle the load anymore)
Anyway, as I mentioned before, a beeping computer with no video is actually a common problem and is not caused by a virus, or any type of malware at all as some people think. I get calls from customers with this type of problem fairly often, especially from people who have just moved which I’ll explain in a moment.
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Common Root Cause for a Beeping Computer
A beeping computer with no video usually happens when a computer is moved, whether is be from changing residences, or just moving it aside when vacuuming. Most computer cases nowadays are made with flimsy sheet metal. It doesn’t take much to flex the case and cause a part to get ever-so-loose. Parts such as the memory, can creep loose just enough to cause a problem, but you might not ever notice it by look or feel. So it is a good idea just to remove and reseat the memory. I’m not going to get into all the ESD safety concerns here so please do your own homework. All I’ll say is to be sure you unplug the power to the computer and ground yourself to the case.
When you do pull a part, do a visual inspection and blow off any dust with a can of compressed air. For example, when I pull the memory, I blast off any dust and clean the memory contacts with pure denatured alcohol. As for the dimm slots on the motherboard, I blast out the dust with compressed air as well, but then I spray them with CRC QD Electronic Cleaner solvent followed by another blast of air again. Just be sure to use the straw nozzle so you can focus the solvent into the dimm slots. After I am sure there is not so much as a speck of dust inside the slots, I will reseat the memory. You would be surprised how often this fixes the problem. You can pick-up a can of Electronic Cleaner at an auto parts store.
Beep Code Viewer
If you already watched the video, then you know there is a free portable program called the Rizone Beep Code Viewer you can download that will provide you with a description for a variety of beep codes from different BIOS vendors, as well as some suggestions for remedying the problem. Their website is:
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