Hi @louisianagal ,
You need to change the mode from UEFI to Legacy mode so thatyou can boot from a USB or DVD.This is from the User Guide:
How can I start the BIOS setup utility?
To start the BIOS setup utility:
1 Shut down the computer.
2 Press the Novo button and then select BIOS Setup.
How can I change the boot mode?
There are two boot modes: UEFI and Legacy Support. To change the boot mode, start the BIOS setup utility and set boot mode to UEFI or Legacy
Support on the boot menu.
When do I need to change the boot mode?
The default boot mode for your computer is UEFI mode. If you need to install a legacy operating system, such as Windows, Linux or Dos, etc (that is, any operating system before Windows 8) on your computer, you must change the boot mode to Legacy Support. The legacy operating system, such as Windows, Linux or Dos, etc cannot be installed if you don't change the boot mode
Once you have installed Win 8.1 or 10 you can go back and enable UEFI mode again.