Run System Restore to before you made the changes.
Update the display driver in Device Manager, allowing it to connect Automatically to Windows Updates to search for newer driver.
If driver is current, uninstall it and reboot to reinstall it.
Run the Aero troubleshooter by typing aero in Start search box to open it.
You may need some help from Hardware forum to check the laptop monitor connection. Maybe someone here will know exactly how its done. The wire bundle can come unplugged.