It appears that Lenovo did you a favor with a standard ATX power supply. This was merely a quick visual confirmation based on the gallery pics on their webpage. DO CONFIRM.
I would absolutely look inside and make sure that your motherboard is utilizing standard connectors. For instance 24 pin 2x4 CPU power...and such. Many of the OEM prebuilders use whack a doo connectors just to keep users from changing things readily.