This is truly strange. The thing is that these operating systems will save the keyboard state that was last in use when you shut them down. You can see some pretty odd effects from that.
For example -- If I log on to my notebook computer using remote desktop from my desktop system (which always has NumLock turned on) and then quit, when I start that notelbook up, I have to turn off NumLock in order to use the keyboard successfully to enter my user name and password. But shutting down now will NOT properly save the keyboard state. The only way to get a NON-NumLock state saved in this case is to turn off NumLock at the log on prompt and then shut the system down WITHOUT LOGGING ON!!!
Bizarre, eh? I've tested it a half-dozen times to prove that I can replicate the behavior. I just know that I have to log on remotely with NumLock turned off on the remote machine. Otherwise, I have a wee bit of a hassle in getting a normal keyboard state on the notebook at the log on prompt.
I hope that's not as confusing as I think it is.
I'm wondering if you might have some software (either native to the OS or not) that is switching the keyboard state on you and causing you this problem. Don't know offhand what it would be, though. But if you're running anything at all that changes keyboard mappings, you might want to experiment with it to find out if it's the source of your trouble.
Please let us know what you learn. We'd all like to know.