1. POST tests memory and some other subsystems. This can usually be monitored when it runs each test.

2. After Post and the BIOS makes sure everything works properly, the BIOS will then attempt to read the MBR, first sector of hard drive. When the MBR takes over, Windows is now in control.

3. The MBR checks BOOT SECTOR, where NTLDR locates at. NTLDR is the BOOT LOADER for Windows XP. NTLDR will allow memory addressing, initiate the file system, read the boot.ini and load the boot menu. NTLDR has to be in the root of the active partition as do NTDETECT.COM, BOOT.INI, BOOTSECT.DOS and NTBOOTDD.SYS

4. When XP is checked from the Boot Menu, NTLDR runs NTDETECT.COM, BOOT.INI and BOOTSECT.DOS to get the proper OS selected and loaded. The system starts in 16-bit real mode and then moves into 32-bit protected mode.

5. NTLDR will then load NTOSKRNL.EXE and HAL.DLL. Effectively, these two files are windows XP. They must be located in %SystemRoot%System32.

6. NTLDR reads registry, chooses a hardware profile and device drivers, in exact order.

7. Now NTOSKRNL.EXE takes over. It starts WINLOGON.EXE that in turn starts LSASS.EXE, which displays the Logon screen. When users log on, Windows XP loads the settings of user and executes startup programs.