Windows timing subroutines, how do they work?

If there was someway to turn off the multi tasking of windows, All the
speed/accel/decel subroutines I do in visual basic crash or just lose
thier minds as windows goes off on it's own agenda.

I threatened to put a pulse-generator/port timer to toggle a inbit on
the par port. It would not have worked.

I even used the directX microsecond timer and it "almost" works till
you see the hard drive running and see your motor you are acceling
lose it's mind and break off the endmill.

Linux has became so darned fit-all it is not much better. Someone
suggested a Lite version with less options.

As of now? DOS is the king, Mach2./3 works most the time here with
windows, I was told, maybe wrong that he uses a rtlinux type of kernel
to generate the timing.

For non-critical situations, the directx timer is the best for visual
basic in windows for graphics anyways, why is it not dedicated?. Is
there a magic key? if so I have lots of movement subroutines that
almost work...

David