I got an external Hard Drive for backups last year and with the new computer, I could make use of its eSATA link (much faster than USB).
Only I couldn't. It just wasn't recognised by windows at all.
After much, much, much searching talking about altering BIOS settings and downloading firmware for the SATA controller, the answer was much more Heath Robinson.
It appears that the Western Digital drives need eSATA cables with a really long connector. As most companies put some plastic housing around the end of the cable, it tends not to go far enough into the WD drive. Answer? Get a knife and take some of the plastic off the end of the cable.
Thanks to this guy for having the answer and showing what to do.