Installed Linux Mint (debian) "Reboot and Select proper Boot device..."

"Reboot and Select proper boot device or Insert boot media in selected boot device and press a key "

This is what I get, once I installed Linux Mint from a Live USB pendrive. On this machine GigaByte BXBT-2807 [ http://www.amazon.com/Gigabyte-Intel-Celeron-Barebones-GB-BXBT-2807/dp/B00KR0QHXW/ref=cm_cr_pr_product_top?ie=UTF8 ]

I tried (F12) (keyboard works fine)and I got:

UEFI: Built-in EFI Shell

UEFI: Built-in EFI Shell [yes, twice]

KINGSTONDataTraveller 3.01.00 [my usb pendrive]

PO: HGST HCC4545421AZ45

Enter Setup

Then :

• I tried to boot from the USB pendrive,



• I tried to boot from the default UEFI,
  brief I tried the 4 options (UEFI, HDD and USB live CD), I get the same message. I tried a second UEFI and I Get Shell>terminal-like.




• I tried to remove/reinsert the disky battery to reset BIOS (?), no success.

Now I cannot reinstall Linux nor boot from anywhere.

What should I do ?

Thanks --