Start with the Dell diagnostics (f12 at powerup) - run an extended test on the drive to verity the hardware integrity.

If you see an error such as 2000-0142, the drive has failed and will need to be replaced.

Either way  -- it's likely Windows needs to be reinstalled.

If you need further information, post the system model (Latitude 7470, etc.) and configuration (hard drive, SSD, SSD+ hard drive, etc.).