Will you still have limited access and I assume any personal data can still be accessed as well. Lug.
Oh Yeah...................and your personal data should be backed up somewhere/somehow............just in case.
the OS will not nuke itself, but you will not be able to login. The OS will boot and when you try and login it will kick you right back out. Then again it might not even boot, it could go through the loading phase then die due to expired files.
You will have 30 days notification of expiry. You can then go back to Vista or get the newer Windows 7 that will be available.