The Dell error code 2000 0142 indicates that the hard drive self test is unsuccessful. The failure could be caused by a number of issues, from a loose connection to faulty hardware.
To correct the error, first power down the system. Disconnect and reconnect the hard drive and run the diagnostic test. If the problem persists, plug the SATA cable to another SATA port on the motherboard and refer to Dell Support to download the latest update of BIOS.
Replace the hard drive connector with a verified working cable if one is available. If diagnostics still reports the error code, run disk repair using the command prompt >C:\chkdsk/r/f then perform a full format on the hard drive and reinstall the operating system.