POST facts for kids
The POST, in most computers, is a self-test that checks the OS(s) available and boots from the OS selected. POST stands for Power On Self Test.
A POST usually checks the crucial, files, folders, and components. Once the POST is completed, a selected OS will take control and finish the startup process.
Failure of POST
LKGC(Last Known Good Configuration) reverts to the last non-problematic, successful bootup. It is similar to System Restore, but its primary function is to allow the user to use the computer normally, unlike System Restore, which does not guarantee a fix. Also, LKGC is unrevertable, unless you successfully bootup again.
System Restore works by allowing the user to open a wizard, then select a "restore point". The user must restart for the point to take effect, but the system will start as normal.
POST Facts for Kids. Kiddle Encyclopedia.