The A7V8X-LA motherboard is compatible with SATA I hard drives ONLY.
If you purchase a SATA II drive make sure to check the manufacture website / manual and set the jumper speed so the drive is able to operate at 1.5Gb/s.
Also make sure you are running the 3.15 version of the bios.
The bios is restricted as to what SATA options you can set.