Did you try connecting the drive to a different computer to see if it is the drive or the computer?
After dropping my Iomega 1TB external drive it made a strange clicking/beeping sound everytime I switched it on. At first i thought it might be the usual 'Click of death' but the beeping sounds are periodical. As a last resort I tried taking the case off and stuck the hard drive in the freezer for 2 hours.
When I took it out and plugged it in it still made the beeping sounds even after I gave it a little tap. I left it switched on for a while (plugged in to laptop via USB) and the beeping stopped, a while later the device drivers were installed. Although the drivers are installed windows cant detect the device and so I cant recover my precious data!
Any help is much appreciated, Thanks.