In my opinion, you are unable to use an OS that started out on Pi2, and run it on a Pi3. At least that is what my experience with it told me. I spent the time to upgrade wheezy to jessie, then swap the microSD card, and no go.
A fresh install of jessie is needed. Here is how i did it without using noobs.
1) Obtain the flavor of jessie that you want, full or lite, from the following link
https://www.raspberrypi.org/downloads/raspbian/
2) Format your microSD card for FAT32.
The following is for Windows install.
3) Using the image mounting tool, Win32DiskImager, mount the img file to your microSD card.
https://www.raspberrypi.org/documentati ... windows.md
4) Place the newly loaded microSD into your Pi3 and power it on.
5).......
Image mounter for other OS can be found at:
https://www.raspberrypi.org/documentati ... ng-images/