Troubleshooting System - No Power On

When a computer no longer powers on, it may indicate that there's a problem with one of the internal components. Sometimes, the issue is relatively simple and can be fixed with few minor troubleshooting steps outlined in this guide.
The Problem
Power outage, spikes and other irregularities can often damage components inside of the system. Sometimes the damage may only be temporary and fixable, where as other times it might require replacement of the unit. Manufacturers and system builders do not cover these damages, so the best thing to do is secure your investment by purchasing an UPS unit, a machine that will allow your system to continue running for a short period of time in case of any power outages. Most of these UPS units also include voltage regulators that prevent spikes and odd behaviors that can also damage the system.
If you already have an UPS unit, it is also important to stay on top of it, making sure it's healthy and working OK. Most units come with web based software that allows monitoring and usually displays health status. Just because you have an UPS, doesn't mean your system is safe if the UPS may be at the verge of dying.
Step 1 - Checking the basics
If your system won't turn on when pressing the power button, some of the basic things you can check:
1) Try to plug the system into a different outlet. Preferably in another location, since outlets in the same location are usually running on 1 line.
2) Try using different power cord if you have a spare
3) Check the Switch on the back of the power supply to make sure it's on.
Step 2 - Advanced Troubleshooting - No Light
For this troubleshooting, you will need to take off the side panel of your computer case.
Most motherboards have LEDs that indicate that they're receiving power. If you don't see any LEDs on the board lighting up when the power is plugged in, you may have a defective power supply.
To make sure it's not a loose connection, remove the power cable, ground yourself first by touching the inside of the case, and then re-seat the power cables to the board. These are typically an 4/8 pin generally located in the top left corner of the board, and a large, 24-pin cable located typically in the middle of the board on the right edge.
If you've reseated the cables and your motherboard still does not light up, the power supply may need to be replaced.
Step 3 - Advanced Troubleshooting - Lights ON
If the motherboard LEDs are ON, but the system still refuses to start, you may have a loose/bad switch or a defective motherboard.
For testing purposes, you may use pins from a RESET button on a POWER button to check for switch issues. In order to do this properly, you will need to consult the motherboard manual for the diagram of the front panel connections.
If pressing the RESET button doesn't turn the system on either, then most likely the motherboard is defective and will need to be replaced.
*Disclaimer: AVADirect and its Staff are not responsible for any damage to software/hardware, loss of data or personal injury by following our How-To guides. These guides are provided only as an aid to help you troubleshoot system problems. If you do not feel comfortable performing these steps its always best to send in your system to a local repair shop or contact an appropriate technical support line for additional assistance.