External Hard Drive problem

I had recently bought a WD 500GB MY Book premium firewire/USB external hard drive from Amazon. Everything was working just fine until tomorrow when suddenly I got a alert message saying one of my partition on the hard drive was not being recognised and data seemed to have lost. I tried to stop the hard drive using the external device icon but the drive didn't seem to be recognized at all by the PC and when I tried to restart the computer it crashed until I removed the hard drive physically form the usb port....then once the computer has started if I try to reconnect the drive I get an alert saying USB device not recognizes...USB device has malfunctioned please replace the device. The same thing happens if I connect via Firewire. I have checked my USB ports and firewire ports are working fine with other devices.

Has anyone got any remedy for the situation? Or do I need a replacement?



MY PC specs:

2.4GHz celeron, 2,5GB RAM

WIndows XP Pro, SP2



thanks

RR

It worked before, and now it doesn't? Is there more than one device that might be asking for the same drive letter?

No hat is not the case. essentially the drive went out just after it displayed the message that I://$Mft not found, I was one of the partition of my external hard drive.