Here are some troubleshooting steps that may help.
- First is to try and connect an external USB mouse if you have one available and see if it will work normally or not.
- If the external mouse will work, do uninstall/reinstall the Touchpad driver.
- Open Device Manager and uninstall the Touchpad driver.
- Once done, download and install the latest driver.
- Here's the link: https/download.lenovo.com/consumer/mobiles/tp157w764.exe
- Reboot the laptop once the latest driver has been installed then test it again after the reboot.