Disk Problems

[Foxing Peculiar]

So I've flown back home and brought along my two external hard drives, which I'm trying to hook up to a computer here. (I normally use a Mac, this computer is running Vista, btw).

One of them shows up, no problem.

The other one shows up in the device manager, but not in My Computer. I went into the Disk Manager and assigned it a drive letter, but it's telling me it has to reformat the disk (I think it's using NTFS and not FAT32 or whatever -- I only have a slight grasp of these things).

Can I do that without erasing it? Every time I've ever formatted anything, it's wiped it clean, and considering I have about 400GB of files on this drive, accidentally erasing it would be a BIG problem.

If formatting will erase it, is there another way I can get into it?

[Nak Nak]

So I've flown back home and brought along my two external hard drives, which I'm trying to hook up to a computer here. (I normally use a Mac, this computer is running Vista, btw).

One of them shows up, no problem.

The other one shows up in the device manager, but not in My Computer. I went into the Disk Manager and assigned it a drive letter, but it's telling me it has to reformat the disk (I think it's using NTFS and not FAT32 or whatever -- I only have a slight grasp of these things).

Can I do that without erasing it? Every time I've ever formatted anything, it's wiped it clean, and considering I have about 400GB of files on this drive, accidentally erasing it would be a BIG problem.

If formatting will erase it, is there another way I can get into it?

Formatting will erase everything on the drive.

File system should not be a problem. Both drives are probably NTFS.
What drives are they? Their differences may make it easier to figure out why one works and the other doesn't.

[Foxing Peculiar]

They're both Western Digital hard drives. The one that works is a 250GB, the one that doesn't is a 500GB. Other than the size and the file system, everything else I know to look for is the same (the smaller one is on a FAT32 system, the big one isn't, which is why I thought it might be that, but if that doesn't make a difference, I'm at a loss).

[Foxing Peculiar]

Ok, I looked at the drive in disk manager again and there are some changes:

The drive that does work has a single box (partition, I guess) that says

Video ( F: )
232.88GB Fat32
Healthy Primary Partition


The drive that doesn't work has two boxes. One says:

465.75 GB
Healthy (Primary Partition)

and the other says

9MB RAW
Healthy (Active Partition)

I can't do anything involving the larger partition, either -- I can't access properties, or anything. The only option that's available is "Delete Volume" which I obviously don't want to do. (Edit--) I can mess with the smaller one, and it shows up with a drive letter now, but there's nothing in there -- it's just 5MB of free, blank space.