Tip & How-To about Computers & Internet
This document is intended to help users who are experiencing issues with POST and may have any of the below symptoms.
1. Computer beeps irregularly when the computer is turned on.
2. Computer turns on but does not boot.
Note: Not all computers have beep codes, some of the newer computers have LED's that light up that indicate the error or have a sound file to indicate the error.
A POST failure can be caused by any of the following situations.
1. New hardware conflicting with old hardware
2. Bad or failing hardware device.
3. Other hardware issue. (electrical shorts or incompatibilities.)
Warning: Some of the below steps recommend removing physical parts within the computer. While in the computer it is highly recommend that you be aware of electrostatic discharge and its potential hazards. ALWAYS ground yourself and your equipment. Ensure your computer is unplugged!
Note: Make sure your computer is turning on, if you press the power button and nothing happens (no lights, no sound, no fans, etc.) then this issue is not a NO POST but is an power related issue.
If any new hardware has been recently added to the computer, remove that hardware to make sure it is not the cause of your issue. If after removing the new hardware your computer works it's likely the computer is either not compatible with the new hardware or a system setting needs to be changed to work with the new hardware device.
1. Remove everything from the back of the computer except the power cable. Turn on the computer and see if it beeps normally. If the computer has never beeped also connect a monitor to the computer to see if any change occurs.
2. Check the stand-offs (the metal or plastic insulators) that keep your motherboard off and away from the case or housing. Ensure they are not grounding or shorting the motherboard out. If they are metal, ensure that the cardboard insulators are present. Ensure the motherboard is not grounding out to the case also at any other point.
3. If you are receiving a sequence of beeps consult your motherboard manual or the motherboard manufacturer's website for a listing of different beep codes and their explanation. These beep codes are meant as a method of quickly identifying what computer component is failing or bad.
4. Check to make sure power cables are not grounding or shorting to the case or other components. Ensure all ends are connected properly, securely, and snugly.
5. Make sure all fans are running in the computer. If a fan has failed (especially the heat sink fan for the CPU) your computer could be overheating and/or detecting the fan failure causing the computer not to boot.
6. If you were unable to determine by the beep code what is failing or do not have a beep code disconnect the IDE cables from the CD-ROM, Hard Drive, and Floppy drive from the Motherboard. If this resolves your post failure, attempt to connect each device one at a time to determine which device and or cable is causing the issue.
7. If the above recommendations still have not resolved the irregular POST, start disconnecting your expansion riser cards, these are the cards that are not essential to system operation. Break your motherboard down to the bare basics. Disconnect your floppy drive, CD/DVD ROM, and hard drives Your motherboard basics should have just the following: video card, RAM, motherboard and PSU (power supply unit). If this resolves the issue or allows the computer to post connect one card or device at a time until you determine which card or device is causing the issue.
8. If you continue to receive the same problem with all the above hardware removed attempt to disconnect the CPU and RAM from the Motherboard. Once done insert the CPU and RAM back into the computer to see doing this resolves your issue.
9. Ensure your PSU is of the correct size and power requirements for your system. Many newer motherboards and graphics cards are power intensive. Some newer graphics cards require their own separate power supplies. An underpowered PSU, will also cause system failure. Most new systems will not run well with less than 450W PSUs.
10. If after doing all of the above recommendations you continue to have the same issues unfortunately it is likely that you have bad or incompatible components, in particular RAM. Ensure your RAM is compatible with the motherboard. Many newer motherboards are very specific about what RAM sticks they will accept. Don't mix and match RAM speeds, type, or size.
11. If you have determined your components are compatible, then you have faulty hardware. The next step would be to test each component separately. You will need to find a working motherboard to test RAM with a diagnostic program like Memtest 86+. A faulty motherboard will need to be simply replaced. A bad PSU can only be replaced. Don't attempt to repair a bad or failing PSU. This is quite dangerous. High voltages and hazardous chemicals are present in PSU capacitors and other components – even when main power is disconnected. You can only replace a bad PSU.
12. If you keep getting the same failures after replacing CPUs, motherboards, and PSUs, there is a small chance that one of the peripheral cards is not compatible and causing damage or the card is conflicting with an internal integrated component. If you have integrated video or sound, you need to turn these off before using external cards.
Posted by Archie... on
Aug 21, 2011 | Computers & Internet
This issue can be caused by any of the below possibilities.
Make sure the monitor is on. If no power light (green or orange light) is seen on the monitor display try pressing the power button until it comes on. If no light comes on after several attempts continue to below connections not connected properly.
Computer is asleep
If your computer monitor was on and you stepped away from the computer and upon returning it was black it's likely that the computer is asleep. Try moving your mouse, clicking the mouse buttons, and/or pressing any key (space bar) on the keyboard to wake it up.
Make sure that you are connecting the monitor to the back of the computer in the 15-pin connector as shown to the right or older computer 9-pin connection.
If the computer is properly plugged in, make sure it's getting getting power.
If you are not receiving power from a known working wall outlet and if the power cord is removable, replace it with the one connected to the computer and attempt to power on the monitor again. If the monitor still does not get power or it is not removable, it is recommended that the monitor be replaced or serviced at a local TV / Computer repair shop.
If the monitor is receiving power, check the status light.
If the light is orange or flashing ensure that the monitor is not in a suspend mode by moving the mouse or pressing a key on the keyboard. If the computer does not get a display by moving the mouse or touching the keyboard, turn off the computer and monitor and reconnect the data cable from the back of the computer, and if removable, the back of the monitor. Turn the computer back on; if you still encounter the same issue, continue reading through the other possibilities.
Ensure that the brightness and contrast is turned up or attempt to adjust the brightness and contrast. If adjusting the brightness or contrast has no affect on the monitor continue reading through the other possibilities.
Does the computer beep when it is powered on and/or does it appear that the computer has activity? If the computer does not beep or beeps abnormally it is possible that the computer itself is experiencing a hardware issue or is exhibiting a No Post.
Steps on troubleshooting an irregular POST or no beeps can be found on document CH000607.
If you have followed the above recommendations and are still encountering the same issue, it is likely that the computer may have either a bad video card or monitor. The best method of determining this is to do one or both of the following
If your monitor works on another computer it is safe to assume that the video card or potentially the motherboard within the computer is bad. Steps in troubleshooting a video card can be found on document CH001028.
Nov 26, 2010 | ASUS P4S333 Motherboard
Nov 29, 2008 | Computers & Internet
Nov 21, 2007 | EliteGroup (ECS 915PL-A2) Motherboard
136 people viewed this tip
Usually answered in minutes!