Windows 7: Cannot access 1TB External Hard drive (USB) Crashing windows explorer

Hello i'm kinda a newbie to anything to do with external hard drives and/or Corruption.
But my external hard drive recently has become unusable, When it's plugged it only shows "Local Disk ( G: )" on My computer, with no drive size/space left. (Image to explain, Yes i know My primary drive is full, but i have no external to backup on. Here)

Any interaction with it will cause windows explorer to crash, and forcing to restart windows explorer, looking around the web i see no real fix i feel like trying, as there's around 600GB of data on there i wish to keep.
So i thought it'd be best to get a hopeful fix specific to my problem just to make sure i don't mess-up and lose the data.

The Harddrive itself is a "Hitachi 1tb External Hard Drive", For what model i have no idea, but looks exactly like this image: Here
It's a Dual power-source external hard drive connected by USB 2.0.

the only real problem i had with the drive prior to this problem was i had a little notification when it was connected asking me to scan for errors, i was kinda worried about the possible corruption so i went ahead and left it to scan the 2 billion odd bytes from what i remember , took ages to do but the problem was still there, I saw no issue with any of the files on there after pressing the "continue without scanning" so i just thought it might have been a bug, as the drive seemed normal.



But then after a while this problem occurred and since hasn't been fixed, i can't seem to even format it as right-clicking the drive has the same outcome as double-clicking.


I'd like to thank anyone willing to take the time and help me out with this problem, and try to keep things simple if possible, don't know much about Hard drives.

Hi,

Lets have a look at this in Disk Management - can you open it and attach a screen capture image of it please?

Regards,
Golden

Thanks for the reply, much appreciated, But a tiny update, i've had the hard drive connected a while now, and around 10-15 minutes ago my hard drive spun up (audibly) and a prompt came up asking to scan the harddrive for errors, or continue without scanning, i started scanning.
It's nowhere near done. (Here)

however i opened up disc manager as asked and this is it: Here

Looks as if the drive is empty, i can confirm it's not there was around 300-400 GB Free.
Edit: Just to explain a little more the drive has been connected around 1hr 30Mins Before that popped up.

One thing you need to do is get that drive letter (Y) and the "Active" off the System Reserved partition of the C drive.
Ops, forgot the link: Partition - Mark as Inactive

How was the USB drive formatted to begin with?

I don't really know what you mean about the system reserve?
Edit: So i don't sound like an idiot i know what it is, just don't know what you want me to do.

But the Drive i think was NTFS, It now displays that on My computer since it has began scanning, Along with the Drive name ( Mike's Harddrive G: )

The System Reserved space on your C: drive is marked "Active" and has a drive letter. Remove the drive letter Y: and deactivate the partition. Do NOT try to remove the partition, just deactivate it. (Follow the added link.) Leaving the SR active can cause boot problems.

Restart your system to make sure it reboots.

THEN, we'll look at drive G:

Ah alright Well i don't really want to restart until this scanning of the hard drive G: is done (One mentioned in Previous posts. (Currently at 310 files processed, Looks to be around an 8th of the way)
Is this system reserve active related to my problem, Or just a general problem, because i don't think i've ever messed with it since first boot.

Something has "messed" with it. Windows 7 doesn't normally assign a Y drive nor make the reserve active. Only the boot disk C: should be marked active. When a partition is active, Windows will attempt to boot from it. You may (or may not) have a virus or root kit grabbing your system at boot.

Your external drive G: is correct except it should be NTFS under File System. That's why I asked how it was formated to begin with.

It is displayed on My computer as NTFS, But not on drive manager, for some reason, possibly to do with the scan.

And you said to follow the link attached?
You hadn't linked it, And i'll have to do it after this scan, probably going to take a number of hours.

Partition - Mark as Inactive

Make sure your C: drive is marked Active before you reboot. It's the one that has "Boot" under Status. You should be able to do that from Disk Manager.

Here's a snip of my drives for comparison. And yeah, the scan could cause the missing NTFS. It could be trying to determine the type.