Why do I get no video/POST?

Why do I get no video/POST?
My fans spin, but I get no beeps or video.

There are several things that can cause your system to not POST correctly. Each system is a little bit different, so we will try to cover common issues here. Remember that the issue can easily be a lemon part or simply a wrong setting. Even things that shouldn't cause a problem sometimes do. I once saw a machine that was being shorted out by a bad case fan! Even a power cable or an outlet can go bad. Remember that sometimes, good old replacement/test parts can be the key to finding your issue.

This FAQ is written as if your parts are already installed inside of your chassis. That being said, it is always better to breadboard your parts before including them in the case. This will allow for easier troubleshooting should something go wrong. It is much less time consuming to proceed this way rather then to shove it all in a chassis just to pull it out later if it doesn't work!

Before we start, be sure that your CPU fan spins at all times during testing. Many processors can become useless after just a few seconds of use without a properly fitted heatsink/fan.

These suggestions may not be in the order that you prefer to go by, or in the order that you will find most useful. You may find that skipping around the steps a bit can sometimes be helpful.

1. Be sure that the pins on the monitor cable were not bent. You may want to try a known good monitor as well.
2. Ensure that all connections are tight. Especially check that the video card is seated well.
3. Ensure that your system speaker is connected (or the motherboard is jumpered correctly if the system speaker is integrated on the motherboard) so that you can hear any beep codes that may be trying to alert you to the issue. Additionally, some motherboards will "talk" to you by playing a sound file over the speaker(s), telling you exactly what is wrong. If your motherboard has integrated audio, plug a set of speakers in.
4. If your power supply has a voltage switch on the back (110 or 220), be sure that it is set correctly.
5. Doublecheck all settings with the motherboard manual.
A) Especially check for a "clear cmos" or "clear RTC" jumper. It should be in the "normal" or "boot" position. In addition, check that the RPMs of your CPU fan are supported by your Motherboard. Even an RPM setting that is HIGHER than specified by your motherboard can prevent the system from POSTing.
6. Check your parts for any indications of damage. Motherboards, especially, should be checked for blown capasitors. These capasitors should NOT be bulging at the top or leaking a black "goo" out the bottom.
7. Unplug any keyboard, mice, or other peripherals. Just having a PS/2 device in the wrong port can cause no video!
8. Ensure that your CPU fan is plugged into the fan connector on the motherboard that is marked "cpu fan", "fan1", or something similar.
9. Double check that your RAM is in the appropriate slot. Also be sure to find if your type of RAM has to be put in in pairs.
10. Pull out all RAM. At this point, the motherboard should give you a beep code. If not, then look at the possibility of a bad MB, CPU, or Power Supply.
11. Try a known good video card.
12. Use a logic probe to test for CPU clocking.
13. Test your power supply. This can be done by trying a replacement, using a power supply tester, voltmeter, or any combination therein.
14. Try a known good video card.
15. By looking at the back of the case's motherboard plate, ensure that you have not accidentally placed a metal motherboard standoff where it does not belong.
16. Unplug any IDE cables, floppy cables, etc. from the motherboard. A backwards cable can prevent the system from getting video.
17. Unplug the power from all devices exept for the motherboard. Also ensure that any data cables from those devices are also unplugged.
18. Unplug all wires that go from the front panel to the motherboard. (carefully) Use the tip of a screwdriver, or some other conductive material, to momentarilly short the two pins that the power button should connect to. This will start the machine. If you get video now, check to ensure that these are hooked up right--also make sure that your reset button is not stuck.
19. Remove any non-essential cards in the system. You only require a motherboard, CPU (and heatsink/fan), RAM, power supply, and a video card.
20. Begin to replace any remaining parts one at a time until you are able to get video.
21. Breadboard the system--take the motherboard out of the case, use a CPU (w/heatsink and fan), RAM, Video card, and Powersupply to power system. Be very careful that nothing is going to short out on a conductive surface (or on another part). If it POSTS now, put it back in after carefully checking for shorting points in the case (especially motherboard standoffs).
A) Don't forget to try another Power Supply--even though the fans spin, it can still be bad.

This is not a comprehensive list, but hopefully it will get you pointed in the right direction. Just have patience, and doublecheck everything! Do not take my word for anything that you have not already verified with your manuals!

[color #ff0000]Any errors within the FAQ are mine. Feedback regarding suggestions or constructive critisism is welcome and appreciated.[/color]

Thank you to everybody below for thier contribution to this FAQ (directly and/or indirectly)
gargouille
edfair
pentode