external hd not recognized with vista 64

hi, i upgraded from an xp to a vista 64 ultimate. i have a hitachi 1tb external mass storage device, i moved all my contents to the external hd and formatted and installed vista 64. later found vista not recognizing my external hd, contacted both microsoft and hitachi, both offered solutions that didn't work. when i turn it on, the computer now see's it as a local disk instead of an easy drive, when i try to access it the entire computer hangs and i have to turn off the external hd. tried the external on other xp running computers and it works fine. if you have a solution to my problem please let my know.

 

If the drive is formated in NTFS, it may be a matter of permissions. Go to My Computer, right-click the drive for Properties, Security tab. You must have your account listed under Group/users.

If that checks out, do a full disk scan. In Properties, Tools tab, check now, check both boxes, start.

If you can't do that on Vista 64, do it on a working XP PC.