Windows 7 Boot Process

As Windows 7 starts, it performs below steps to load Windows:

1.       When the computer is turned on, the CMOS loads the BIOS and then run POST.

2.       The BIOS loads the MBR, which indicates the first active partition.

3.       The MBR loads the Boot Sector of the active partition.

4.       The Boot Sector of the partition points to BOOTMGR file so it could be loaded.

a.       The execution of BOOTMGR performs the following actions:

If there is a hidden folder BOOT (created in the Vista installation) with a valid content, then it locates the BCD (Boot Configuration Data) file which contents Boot options of the Windows 7.

b.      If there is more than one OS installed on our PC (other Windows 7 or any other Pre-7 version of the Windows). It shows you a menu to choose the desired OS.

5.       When you select Windows 7, BOOTMGR transfers the control to the Windows Loaded (Winload.exe) or (winresume.exe in the case the system was Hibernated).

6.       Winloader loads drivers that are set to the start at boot and then transfer the control to the Windows Kernel and Windows is started.