Anychance you could give more info. Always useful are....
- OS version
- Enclosure manufacturer.
- Enclosure interface, Firewire/1394a, USB2, SATA?
- Enclosure chipset manufacturer and version, eg Cypress Semiconductor, Initio, Oxford, Agere, other I can't remeber off hand...
- Is the drive spinning up when powered?
- Does the drive work when installed inside the computer?
The last couple aren't strictly necessary, but they do show that you had a go at remedying your issues.
Get back to us and we'll see what we can do