Windows boot error message:-  root system 32 ntoskrnl.exe missing or corrupt.

How to fix missing or corrupt ntoskrnl.exe file

Insert your Xp disk into the CD drive, choose the boot from command prompt option in the menu that you are presented with

At the command prompt, type in the following:

copy d:\I386\Driver.cab c:\system32\ntoskrnl.exe /v

where d is the letter of your cd drive

press enter

Take the CD out when verified and reboot your computer

Alternatively

Get a copy of this file from another PC and copy it onto a bootable floppy disc then boot from the floppy and at the dos prompt:

copy a:\ntoskrnl.exe c:\windows\system32

then reboot system