Redownload the installer... it seems that the copy you have downloaded is incomplete or corrupted.

For reference, the "bitcoin-0.15.1-win64-setup.exe" I downloaded from bitcoin.org (https[Suspicious link removed]) is 14,325,736 bytes

Right-click the .exe and select "Properties" and see what the size is... if it is less than that, your download was incomplete/corrupted.