XP was the last Windows version where Bill Gates would let you anywhere near the timer interrupts. The moment he lets you in there he can't time-slice you if you start misbehaving. You can hack into a 1kHz interrupt but Bill can keep you waiting if he thinks he needs more processor time. Bad news if you want to keep those steppers rolling. Without control of the interrupts, you have to add another processor between Bill and your motors, one where you are in control.
Or something like that