https://de.ifixit.com/Anleitung/HP+ProBook+4520s+Hard+Drive+to+SSD+Replacement/71389
HP ProBook 4520s Hard Drive to SSD Replacement - iFixit Reparaturanleitung
If your HP ProBook 4520s shuts down without warning, you may have a hard drive error and need to replace the hard drive.
hp probookhard drivessdreplacementifixit