help - driver installation problem

I think this is place for driver installation problems,if not please redirect
as appropriate if someone knows.

Q:We have mouse driver, during upgrade of the product we uninstall the
drivers and install the latest drivers.This process prompts for a
reboot.After reboot the device manager shows that the mouse is associated
with the system drivers(Microsoft PS/2 port) rather than ours,but our driver
are loaded.
Do we have to necessarily do a reboot twice? or could there be a problem in
the drivers? If so, how could i could i confirm this?

Points to note:
1. OS - WinXP - Sp2
2. Mouse port is PS/2
3. The uninstall of drivers requires a reboot,but we dont want to do that
since this ends up in doing two reboots one for uninstall another for
install.Also, an important point to note is without rebooting for uninstall
and doing an install,device manager shows the mouse associated with our
device.The problem occurs only after the reboot
4. Our uninstall does not reconfigure to make the device use system drivers
is that something that need to be taken care to make the later install
configure cirrectly after reboot?

Any insight would be highly appreciated.

thanks
Venkat