Did you also change the port? (i.e. from PS/2 to USB)
The port may share rescources with another device in your system. If its USB, try a different USB port. USB mice might cause intermittent freezes/unresponsiveness. Get a USB to PS/2 adapter and use it as a PS/2 mouse. Also, some mice require proper drivers from the manufacturer. It will function with built in MS drivers, but responsiveness might benefit from having the correct drivers installed.
Last resort is to learn all the windows keyboard shortcuts and declare your independence from rodents.
Good luck!