1
Look at the function keys (F1 - F12) on your keyboard, if one of those keys has an icon that looks like a touchpad with a line through it, press that key or Fn + that key to test if that enables the touchpad.
2
If that was not the problem, the best option is to go to the support page for your laptop on the Lenovo website to download and reinstall (not update) the version of touchpad drivers they provide.
If you have any difficulty locating that support page, click your Start Button, then just type msinfo and press Enter, please provide a screenshot of the resulting System Information window.