MD500 GB not working

[Taffvader]

my MD500GB hard disk is not working light is permanently on and noise but PC doesnt recognise
it

 

[Phillip Corcoran]

Your external hard drive may have developed a fault. Test it with SeaTools for Windows:
http://www.seagate.com/gb/en/support/downloads/seatools/seatools-win-master/