Yes you can but BE VERY CAREFUL.
Here is what you want to do.
First Back Up your registry.
Then Restart windows in safe mode.
If it is not in safe mode windows will automatically
replace the new one with the default.
Have your new replacement file ready in Windows\System32
folder.(It should be ntoskrnl file). Rename the original
to something else like "originalntoskrnl".
After pasting your new ntoskrnl file restart the computer.
(Be careful some require ntoskrnlSP file for SP1 equiped
Windows.)
