Try other usb port, or other computer and see whether the hdd is detected. If still not, try to go to device manager ( http://www.computerhope.com/issues/ch000833.htm ), and then assign a drive letter to the hdd. After that, try to access it from Computer, if not able to access it, format it (use quick format) and then use this program to recover your files.
http://www.asoftech.com/adr/

Turn the computer off without the external hard drive being plugged in.
plug the external hard drive in a usb port, power up, the systems post boot up will find the drive and inform windows what hardware is installed.
When windows boots up, it will look at all the hardware and find the external hard drive, when windows finishes booting up you should be able to see the drive in my computer.

If you can't access your files, target="_blank"> target="_blank">Data Recovery for Windows OS

Where can i find the software for my smartdisk firelite 160gb