How do I get my eSATA drive working in Windows 7 x64?
As a question - this external SATA drive - does it have a separate AC power supply? You mention it working with USB so it is obvious the drive works only when you hookup via eSATA it doesn't. Does this drive attempt to obtain both power and data off the port? They require a special powered eSATA port and your eSATA port may not be powered.
For example, the Seagate GoFlex eSATA requires such a port.
It is incompatible for an odd reason that's not worth troubleshooting...
I've used USB as an alternative for a while. But, it now seems Windows 8 natively supports my eSATA!