Not a silly question at all. If your current mouse is a standard one running off windows own drivers then just turn off your PC disconnect the mouse, connect your new one and re-boot your PC. It will work as a standard mouse until you go into mouse properties and update the driver supplied with the new mouse.
If your current mouse has it's own drivers then remove these first before doing the same as above. When you remove the drivers your mouse will continue to work but in basic form from window's drivers.