3. Provide the built-in Administrator account password.
4. Copy a fresh copy of the ntoskrnl.exe file from the CD onto your HDD using this command:
copy [d:]\i386\ntoskrnl.ex_ c:\windows\system32
Note: This command assumes "c:\windows" is where XP is loaded on your hard drive ... adjust accordingly if your computer is different; [d:] stands for the letter of the CD-ROM drive in which the WinXP CD is located; the file "ntoskrnl.ex_" is a compressed file as indicated by the last character being an underscore character; when in the Recovery Console, the "copy" command automatically expands compressed files on the CD to the HDD.
Type "Exit" to close the Recovery Console and restart your computer. Take the CD out of the drive so that the computer doesn't start from the CD again. I'd futher suggest switching the first bootable device in the BIOS to IDE 0 to lower the boot time.
If the problem was simply a corrupted ntoskrnl.exe file, your computer should now be back to normal.