Irrecoverable Hard Drive

Hello,

I had an old Dell computer when one day the hard drive stopped booting (Seagate ATA-100 ST9100823A).  I've since bought a new computer, and am giving the hard drive one last try.  I've bought an external USB hard drive enclosure (Super slim external storage system).  The light on the external drive case is now flashing red/green in quick succession, which tells me it is plugged in properly, but I hear no noise indicating the drive is functioning.  When I try software such as SeaTools or ZAR, the drive is listed (sometimes called Generic Void Disk), but with a capacity and size of 0 bytes.  In Vista, the old drive does show up under Disk Management, but I can't initialize it no matter what I try.  I've tried everything I know to access the data on the drive, but it looks hopeless.  Any ideas before I toss this old drive?

Thanks!