I have just bought a PC DVD Rom copy of Dead Space 3 but it wont load

I have bought the DVD rom for Dead Space 3 and am following the instructions. When I type autoload.exe the install screen comes up and I click install. This appears to have loaded the origin software but I am unable to launch the actual game. It doesn't even look like the game has loaded.  Additionally I have not been asked to type in my serial number. Nothing seems to be happening.

Is there a way I can load the software online and then use my purchased product key/serial number  to validate it?

Alternatively what should I do to launch/activate the DVD copy that I have just bought.