Booting Process & Windows Installation

Windows XP Installation Screens
http://www.microsoft.com/windowsxp/using/setup/winxp/install.mspx#beginBoot Sequence

Boot Process Flash Video :
http://tc3.hccs.edu/ScottJ/ClassWebPages/Demos/XPBootProcess/2272_XPBoot.swf

Boot Process Diagram:
http://www.geocities.com/asoke_dasgupta/boot-xp.html


Exactly what procedures does Windows XP execute during its boot process?

Solution

The Windows XP boot process consists of five basic phases:

1. BIOS/POST. The system boots, loads the contents of the BIOS ROM and executes the Power On Self Test (POST). This is not specifically an operating system process.
   
   
2. MBR. At least one bootable device must contain a Master Boot Record (MBR), the first sector on a hard disk drive, which starts the the process of booting the computer. The MBR also contains a small amount of code that executes the files needed to load the operating system.
   
   
3. NT Loader. NT Loader (NTLDR) executes NTDETECT.COM for a very basic hardware check (CPU capabilities, BIOS capabilities). Then it reads BOOT.INI to check where the operating system is located. Based on the results from NTDETECT.COM, the Hardware Abstraction Layer (HAL) is loaded, which prepares the Windows XP kernel for adapting to the situation in the best way possible.
   
   
4. NTOSKRNL.EXE. This file is the kernel of the operating system Windows XP. The kernel is responsible for loading, executing and communicating with device drivers. After the kernel is loaded, services and drivers will be started.
   
   
5. Logon. After all the services and drivers have been loaded, the logon screen or welcome screen of Windows XP will appear. When users log on, Windows XP will load the settings of that user and will execute any startup programs.

In the following table you will find an overview of typical errors that might occur during the boot process of Windows XP, and their possible causes.

Typical errors:	Typical causes:
Beep codes, system hangs during POST.	Wrong BIOS settings, HDD inaccessible, hardware failure.
"Invalid system disk", "Operating system not found".	Floppy in FDD, no partitions defined on HDD.
"Missing Operating system", "Cannot load x:\windows\system32\hal.dll".	BOOT.INI incorrect or damaged, NTLDR and NTDETECT.COM not present in the root of the active partition, BOOT.INI incorrect or damaged.
"Cannot load x:\windows\system32\ntoskrnl.exe", blue screens with "STOP errors", error message if driver or service fails.	NTOSKRNL.EXE is missing or corrupted, bad drivers installed, possible hardware failure.
Cannot logon, error message that application fail to start.	User profile incorrect or damaged, software problems.