Hard disk issue,unable to detect

Hello, i have a320gb harddisk,i cant access it,once i plug i see the drive but cant open it,if i double clik i get only a mess to format it,i cant format my datas are in it,now and all that drive notification even is not shown,but my harddisk gives a little vibration as if a small motor runs inside and the led's glow in dim and bright,harddisk gives reaction and light glows but no response in pc.my hardisk is not identified,unable to open it too as there is no screw arrangements,so icant do other methods and that cmdprmt method also,help me guys with ur knowledge