Ensure that you unplug all external peripherals and then turn on the system.
Let us know the following details:
1. Is the hard drive detected in BIOS?
If it is detected, ensure that hard drive is selected as the first boot device.
2. Have you made any hardware change recently?
3. Are you able to boot the system in safe mode?
Turn on the system and tap F8 for advance boot option. Select Safe Mode.
Thanks & Regards
message edited by DellManshuS