WD 320GB HDD wont work

[arcetrex]

Hello, pretty confusing for me since i dont know too much about computers but here goes i have a WD 320Gb HDD and every time i try to copy a file to different location it fails (Different reason every time but its favourite is that some of the information cant be read or written) it seems that i cant back it up to anything and when viewing the files they will systematically disappear but not delete has anyone had this problem and more importantly how can i fix it? p.s. only 25Gb used on it and this happens with both windows and mac

 

[Ubrales]

Download and run "HDTune" on this drive and check its health. It may be failing.