Prevent Auto-Detect setting COM port as mouse

[MM]

Have XP Pro machine, PS2 mouse and PS2Keyboard.
Machine is also connected to device via COM1 which
provides serial data stream.
The problem is that when XP starts, and should the
connected device happen to be dumping data, XP auto-
detects and configures a mouse on this com port!
The data stream then over-rides the real PS2 mouse, and
locks out the application software which should be using
com1.
Frigging great!

Any suggestions?

MM