my device installs as a mouse

Hi all, I have developed an external module that plugs
into the serial port of a host computer. The device
continually sends information strings to the host. If the
host computer is a Windows machine and the user re-boots
with the external module running, the OS automatically
detects and installs my device as a mouse, which it is
not. What can I put into the serial strings sent to the
computer that will tell the OS not to install a mouse
driver, and to leave the Com port alone?

Many thanks!