Windows Kernal Question

[Uriel]

I remember reading somewhere (possibly on hl2.net forums) that new versions of windows are built off the same kernel that has been used for a quite a while and needed to be re-written.

Is this true? and how is windows 7's kernel different from previous versions?

 

[AtomicSpark]

List of Windows Kernel Releases
http://en.wikipedia.org/wiki/Windows_NT#Releases

What is a Kernel?
http://en.wikipedia.org/wiki/Kernel_(computing)