The replacement of the hard disk is easy and goes in a flash. After replacing reinstall the system software of the PS4 is necessary. Here you lose all data. Scores can save her previously on a USB flash drive or upload to the cloud by Sony. Furthermore, a small Phillips screwdriver is required for replacement of the hard drive, and a USB stick (FAT32) with ~ 0,9GB free space. Previously a file with a size of approximately 760MB must be down gladen for reinstallation.
We have attached two links of Sony - so you come from - and after 20 minutes your console is again fully operational and has gained powerful memory.
1) installed a new hard disk (source - Sony): [...]
2.) Reinstall the system software (Source - Sony): [...]