Well the only thing to do if the laptop is new.
And it contains a sata 2.5" hard drive is to take it out of the laptop.
You could then connect it to a tower based system via its sata ports and a cable, and sata power connector from the Psu of the tower.
You would then have to run partition recovery software such as found here http://www.easeus.com/
You must have a drive in the system with enough space so the image or old structure of the formatted 2.5" drive can be reconstructed to it.
1.Run,install Easeus
2. Select drive to recover 2.5"
3.Select the other drive with enough space to store the image of the 2.5" drive rebuilt.
4. Once done you select the image and write it back to the 2.5" drive.
If all goes well then the drive should return back to its state before it was formatted by you including the two partitions C: and D:
Once done it can be disconnected from the tower and placed back in the laptop.
A hidden partition normally does not show, but if it does and appears blank on opening it in windows it is because the image is hidden to windows to avoid deletion.
Failing that it`s a case of buying a full disk version of windows, or asking the company who made the laptop to provide you with an os install disk that they may also charge you for.
Good luck.