Greg's mouse cursor is freezing and it's making a loud audible noise. Leo says he suspects the mouse is experiencing a hard crash of the mouse. Unplugging the mouse and plugging it back in will fix it. It's also a sign of a worn out mouse cable, causing connectivity issues. It could also be a problem with his USB plug, or even the USB controller chip on the motherboard. He should check the drivers. And then, try to get a cheap PCI USB card and see if he can make it work. If it does, then he'll know it's the motherboard USB controller. But Leo suspects it's the mouse drivers. So he should uninstall the driver in the device manager and reinstall them (obviously download the drivers first).
Also, if he transplants another hard drive into his computer, then the Windows install is looking for hardware that doesn't exist and problems like this can happen. So he should format the drive and reinstall Windows.