The issue is not the CPU but either the BIOS and/or O/S. It's possible WD might require a special driver. You should check with them. Asus should be able to duplicate the problem and issue a BIOS update as should Microsoft if it is an O/S issue. SATA3 is backwards compatible.
Thanks techguy for your prompt answer.
It must be the BIOS, since WIN10 is using a Microsoft driver ver. 10.0.10240.16384. Driver date: 21/6/2006. WIN10 recognize the hard disk.
The hard disk is from 2008.
WDC WD1600HLFS-75G6U0 ATA Device. SATA type SATA-II 3.0Gb/s. ATA Standard ATA8-ACS.
Serial Number WD-WXL708050268. Firmware Version Number 04.04V01.