Computer Doesn’t Boot

So you’ve carefully selected your parts, watched countless youtube videos, and have built/upgraded your PC, and it won’t boot. Windows won’t load, or maybe you get nothing at all on the screen. Assuming there is no fire, lets go through some troubleshooting steps.

  • Unplug EVERYTHING from the motherboard except the CPU, power supply cables, speaker connector (if speaker isn’t onboard), power switch connector, and cpu fan connector.
  • Turn it on, you should get 1 beep that repeats about every 2 seconds. That means there is no memory installed.
  • If it doesn’t turn on, unhook the power switch connector, and try touching the 2 power switch pins with a metal screwdriver for 1/2 a second. Yes, I’ve seen bad power switches.
  • Still won’t turn on? verify that the brass stand-offs under the motherboard are installed only in places that have screw-holes. If you have a standoff just pressing against the back of the board, it can short things out. Check out the yellow arrows here: http://img.tomshardware.com/us/2006/12/14/how-to-build-a-pc-part-3/case-locations.jpg
  • Still nothing? You have a bad motherboard or power supply. There is a slight chance of a bad CPU, but unless you’ve damaged it during the installation, probably not. Try a power supply from a friend or perhaps an older PC.

So lets assume though that you did get that repeating beep. You’re on the right track, lets continue.

  • Turn it off and Install the minimum amount of memory, check the manual if you’re not sure.
  • Turn it on, you should get 1 long 3 short beeps. That means there is no video card.
  • Turn it off and Install the video card, make sure to connect the extra power connectors if needed. At this point you should also be verifying the power supply requirements for your video card, make sure the PS is large enough. Hook up a monitor.
  • Turn it on, you should get something on the display. Turn it off and Attach keyboard and mouse.
  • Turn it on again, go into the BIOS, reset it to defaults. Your BIOS might have optimized defaults and normal/safe defaults, or something similar, use the safe defaults. Attach HDD, and turn back on.
  • You should boot into windows (or not if your disk is new). You might need to go back into BIOS here and enable/disable AHCI, depending on how it was set when you installed your OS. Doesn’t boot either way? replace HDD cable with a different one. Especially if you did a lot of cable management and bent up the cables or are clumsy. If you got this far, you’re probably in good shape. Keep installing parts, pretty much one at a time.

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