Bootstrap loader & Windows Boot Process:

A Bootstrap Loader (BSL) is a small program that can be activated immediately after a microcontroller has been powered up, in order to load and execute another program in a well-defined manner. The bootstrap loader is hardcoded into the micro controller.

After the micro controller's bootstrap mode has been activated, a loader program can be used to store some routines on the micro-controller. In the next step, those routines are used to upload new firmware and save it in the program memory. This provides an easy way to upload new firmware.

Windows Boot Process :

Windows boot process starts when the computer finds a Windows boot loader, a portion of the Windows operating system responsible for finding Microsoft Windows, and starting it up. The boot loader is called Windows Boot Manager (BOOTMGR). Prior to Windows, the boot loader was NTLDR. NTLDR parses the Boot.ini file to determine the location of the operating system boot partition.

When you switch on the power supply, the Windows operating systems program gets loaded and takes over the PC's control. It provides the communication link between your computer hardware and the software that you use. For example, when you tell your spreadsheet software to save a file, the operating system instructs the computer hardware how and where to store, namely, in the hard disk, etc.