External HDD empty?

Hello all. First time poster here. I did a search and I didn't quite find anything that matched my problem, so I hope this hasn't already been covered.

I just got a new computer that is running Vista. On my old computer, I had a Lacie 500GB external hard drive (FAT32) hooked up that worked just fine. When I hooked the hard drive up to my new computer, Vista immediately recognized it and offered to download the drivers (or something like that anyway) and so I accepted. Upon Vista saying the driver installation was complete, it let me view the hard drive. . . but it says it's empty. I had about 150GB worth of stuff in there. I tried restarting and switching USB ports but nothing worked.

My friend suggested that maybe Vista couldn't read FAT32 and to hook it up to a Mac and transfer all the data to another hard drive and then reformat the one that isn't working from FAT 32 to NTFS. So I tried hooking it up to a Mac running OS X, but it too said it was empty.

I don't think the hard drive is ruined since it was working fine before I switched computers. Any suggestions? Also, is it ok to reformat a hard drive from FAT32 to NTFS while there's still data on the drive, or will this erase the drive?

Thanks.

Can you remove the enclosure and hook it up directly to the computer?
It might be a bad enclosure.

As far as the converting to NTFS, yes, there is a utility included with windows to do that (do a help search for the "convert" command), and it should work on external drives but you have to be able to see the drive as a letter to do it. Since you can't see it on a different computer (have you tried it on another windows box?) futzing around with drivers and whatnot sounds like your only option. If you absolutely need the data, removing the drive from the external case and connecting it up that way to use a recovery program is also an option (though not ideal)

Are you saying this utility will let me format the drive even if the drive without losing data? Or is this the utility I would use once/if I were able to get all my data off the drive?

My computer can see the drive and it assigns it a letter. The Mac I tried it on did the same thing. They both could see it. It's just that they both say it's completely empty.

Agree with MrLinux. I was trying to correct the misconception that FAT32 can't be converted to NTFS without losing data. In your situation, running a recovery program first is definitely the way to go. Make it NTFS only if you need to store files over 4gb.