If you have installed the software Samsung Kies on your computer in order to manage your backups and maintain contacts, then you will have the following issues with the Samsung Galaxy S7. Samsung Kies will not recognize the Samsung Galaxy S7.
The reason for this is that Samsung Kies does no longer supports the new Samsung Galaxy devices since the S6 model. Instead, for these new devices, as well as for the Samsung Galaxy S7, the Software Smart Switch is available. You can download Smart Switch for your PC and the Samsung Galaxy S7 as follows:
Once you have the software installed on your PC, you can connect the Samsung Galaxy S7 via USB cable to the PC. Smart Switch will recognize your phone and offer you a limited range of options for backup, recovery etc..
You now know how to proceed when Samsung Kies does not recognize your new Samsung Galaxy S7.