POST is the Power On Self Test, which is designed to run on all computers when the power is first turned on, and before the system boots to the Operating System. If the computer fails to successfully complete the POST, the boot process will be halted.
NOTE: Symptoms of a failed POST can include the following:
- When the computer is plugged in, the Power LED indicator turns on but the Hard Drive LED indicator does not flash, remains completely on (a solid LED) or shows no activity at all.
- The Caps and Num Lock LED indicators do not turn on when pressing the buttons on the keyboard.
- No display on the LCD screen.
Follow these troubleshooting steps to determine the issue:
IMPORTANT: If model-specific information is required to complete any of the steps in this solution, refer to the operating instructions supplied with the product. Manuals are posted on your model support page.
- Turn the computer off and disconnect all peripheral devices and remove all optical and flash media.
- Turn the computer back on.
- Check the Power and HDD LED indicators.
- Tap Num Lock and Caps Lock keys to see whether the Caps Lock or Num Lock indicators turn on and off.
NOTE: The Caps Lock or Num Lock indicators will only work only if the POST is successful.
- Attempt to access the BIOS .
- Remove any third-party Random Access Memory (RAM) modules that may have been installed.
- Attempt to start Recovery Process.
The troubleshooting steps listed above should resolve your issue. If you have completed all of the steps and the issue is not resolved, service may be required.  Go to Product Repair.