Does the drive show up in Disk Utility and/or System Profiler and just doesn't mount on the desktop, or is the drive not even recognized by either of those two utilities?
Please be sure to answer the questions asked, as they're asked for a reason, and not answering them will only get them asked again... all we know right now is you've got a SATA hard drive connected to an OWComputing SATA card that either, a) won't mount, or b) isn't recognized by the computer at all.