BIOS Question:

Answer #1
For the person who still has no idea about the BIOS on your PC, notice when you first turn on your PC or laptop a few screens pop up. It might be a logo such as DELL or HP or ASUS, Tyan , AMI BIOS, AWARD BIOS etc. You might also see a memory count . This is all part of the POST (Power On Self Test). POST is a test the BIOS runs before it hands over control to the OS (Operating System). You can see more of the post if you disable the logo option in your BIOS. Otherwise just know that if you see a logo the POST is running.

Answer #2
POST stands for Power On Self Test. In modern BIOSes the POST code is a very rough indicator of the progress of the BIOS boot flow. While there is some testing that occurs during BIOS boot the vast majority of BIOS work is discovery and enumeration/setup of the various I/O interfaces and preparing for the hand off to the operating system.