From USB to HDD

[Fronzo]

Hi everybody, I googled a lot my problem but I couldn't find anything.
I installed Mint into an USB stick, how can I copy the entire OS into an empty HDD?
I already tried with Gparted from a live CD (I copied the ext4 directly into the empty HDD), but the grub failed, I tried with some codes to solve the problem but I didn't manage it.
How should I do that? Did I err by using Gparted?

@EDIT: the USB is: {single ext4|swap|NTFS}.

[edwardr]

What you really need to do is to install Mint onto the hard drive rather than copy it onto the drive. Install the hard drive into the computer where the hard drive is going to reside. Then boot up that computer into a live session of Mint using the USB stick. In the live session, on the desktop, you will see an icon for the Mint installer. Double click on that to run the installer and install Mint. Be warned that the default install option to use the entire dick will erase anything on the hard drive, so be sure the drive does not contain any files you want to keep.

[computerbob]

The 1st 512 bytes of that blank hard drive have to be built by an installing program. This area will contain information about booting and your partition table. Operating systems only boot from active partitions. In linux terms, the boot flag has to be set. You probably need to be aware of these things and know that copying files to a drive does not make that drive bootable.
Also your USB stick has to be bootable and your computer has to be able to boot from a usb stick, otherwise, burn the iso to a dvd.