Original post : BootGuard 2TB Data Protection.
BootGuard by NeoSmart Technologies
This PC has been prevented from booting in legacy mode to protect your data.
Please re-configure your UEFI firmware (aka "BIOS setup") to boot in UEFI mode.
Error Code: BG-2TB
More Information: http://neosmart.net/wiki/bootguard-2tb/
Press CTRL+ALT+DEL to restart