Dedicated COM port, stop OS from sending data?

Archived from groups: microsoft.public.windowsxp.general (More info?)

I'm attaching seral devices to a WindowsXP system (COM ports via
Prolific USB-Serial) device. I've had two probems:

1) Windows thinks the GPS is a serial mouse, used /NoSerialMouse switch
and that got fixed.

2) Now I have a serial device that usesed the first byte sent to it to
autobaud, it get's confused since windows appears to send something out
the port.

?? Is there a way to flag these ports as allocated for a user program
to run later, ie. no probing?

Thanks,
Jon