What is UEFI?
UEFI (Unified Extensible Firmware Interface) is a standard firmware interface for PCs, which designed to replace BIOS (basic input/output system).
When the PC starts, the firmware interface controls the booting process of the PC, and then passes control to Windows or another operating system.
Microsoft Windows 8
Microsoft Windows 8.1
How to Enter BIOS setup or UEFI firmware?
You can enter BIOS setup or UEFI firmware via traditional method:
Boot the PC, while the firmware starts to run, press F2.
However, computer boots fast, maybe you often miss the trick to press F2. You can enter UEFI firmware from windows 8 or 8.1. Take windows 8.1 for an example, steps are described as follows,
3. Click Update and recovery.
4. Choose button Recovery.
5. Then Restart now.
6. Options menu will be seen after executing the above procedures. Click Troubleshoot.
7. Focus on Advanced options.
8. Click UEFI Firmware.
9. Choose Restart.
10. Select Setup under the Tab App Menu.
Note: Lenovo preloaded Windows 8/8.1 is set up with UEFI boot. If your computer is not fitted with UEFI boot, you can only enter BIOS setup or UEFI firmware via the traditional method.