You press the power button on your computer and nothing happens. Few computer problems are more frustrating than when your computer won't boot. There are many reasons why a computer won't turn on and often very few clues about what might be the problem.
The only symptom is usually the simple fact that "nothing works" which isn't much to go on. Add to this the fact that whatever is wrong could be an expensive part of your PC to replace - like the motherboard or CPU. Try to be calm, there is a good chance its a simple problem you can figure out.
1. Does the computer show any signs of power?
Are fans running, lights on? In the case of there are no signs, it may be a faulty power supply. Here are a few things to try. Unplug the power cord to the PC, wait approx 10 mins and plug back in. Does the computer power on now? If so, it may have been a power surge that the PC experienced. You may want to invest in an Uninterruptible Power Supply unit.
2. Is your computer turning off by itself immediately or at some point before the operating system loads?
If so, you may be facing anything from an electrical short to a serious hardware issue. Open the computer case and inspect the wiring. Make sure none are chafing or exposed to direct contact with metal. Some times connectors can become unseated. Inspect and reseat all connections. Just because the unit powered on then off does not mean the power supply is good, it still maybe faulty.
3. Does the computer beep shortly after powering on?
If you’re lucky to get beeps, you can use those to determine the cause. The most frequent problems are memory or videocard issues. A list of codes and their meaning can be obtained from the chart listed on this page http://www.computerhope.com/beep.htm
4. PC powers on but does it display some codes and not boot operating system?
These codes are called POST (Power On Self Test) codes. They are usually specific to the manufacturer. It’s best to call the manufacturer support at this point. Although sometimes the codes can point you in the right direction. In the case of a “No hard drive connected” error, you can try reseating the connectors on the hard drive and test again.
5. Computer turns on but is there an error message prevents the operating system from loading completely?
If your computer begins to load Windows but then stops booting and displays an error message, your best bet is to contact the manufacturer's support or troubleshoot the problem based on the specific error message. You may have to use a restore disk in this case.
Hopefully you are still calm after reading these resolutions. Let us know if you have other problems by leaving a comment below.