Troubleshooting POST Problems
My computer won't start. Is this a hardware problem?
While troubleshooting a problem and determining if it's hardware or software can be tricky, there is one easy test that works a large percentage of the time. Did your computer beep at you when you tried to start it?
Almost all computers run a series of diagnostic tests called a "Power On Self Test" (or POST) when they start up. These check everything from the motherboard to the keyboard. Only after POST is passed does the computer try to start up the operating system. When the POST is successfully completed, the computer beeps once.
If the computer beeps more than once, or if it doesn't beep at all, it means it failed the POST and never even got to the operating system. That indicates a problem with the hardware, or occasionally the BIOS, a small program burned into a read only memory chip (ROM) that controls the most fundamental interaction with the hardware. The BIOS is the program that runs the POST, among other things. If the computer has started successfully before, it's a good bet that your problem is in the hardware.
If the computer beeps more than once it's trying to tell you what's wrong. Each BIOS vendor (such as AMI and VIA) has their own "Beep Codes", but here are some common examples of what the codes mean. For example a long, continuous beep usually means a stuck key on the keyboard or a problem with the system's motherboard. Check your computer's manual or look on the BIOS company's web site for a chart of what the beeps mean.
For more information on POST/beep codes, visit ComputerHope.com, a web site that provides free help to computer users. You can find the information on beep codes at http://www.computerhope.com/beep.htm