Vista shouldn’t be a problem, Disk Management is pretty much the same as the one in XP. USB has a bad habit of rejecting HDs with problems that would normally be corrected by error checking if it was hooked up directly to the computer.
If you’re not hearing a constant “ZIP CLICK, ZIP CLICK, ZIP CLICK” or if you’re not feeling the gyro forces when it power up then chances are it’s just data corruption that needs error checking.