Hard drive not recognized

I have hard drive connected with a USB to my Windows 7 computer.
I got a message Scan and Fix (recommended) or Continue. I selected the Scan and Fix. Now I cannot access the drive.

Below is what I've tried so far. Any help will surely be appreciated.

Microsoft Windows [Version 6.1.7600]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.

C:\Windows\system32>g
'g' is not recognized as an internal or external command,
operable program or batch file.

C:\Windows\system32>chkdsk /f g
The drive, the path, or the file name is not valid.

C:\Windows\system32>chkdsk /f g:
The type of the file system is NTFS.
Unable to determine volume version and state. CHKDSK aborted.

C:\Windows\system32>