The procedure is for the Lenovo Netbook but may also work with other brands in a similar way.

  1. Insert boot media and start installation
  2. When prompted, select Custom/advanced setup
  3. Install on partition where ‘Lenovo’ volume sits

This will add the new OS and keep the older for dual-booting.

Note:
partition 1 = general data partition
partition 2 = Lenovo partition
partition 3 = OEM reserved volume