Hi lynx4896!
You should install a firewall and antivirus software, just for the safety of your system lynx!
I am not sure what might messed up with your installer, it could be an issue with your windows installer.
Let's try to install the game via Origin:
At first, download and install the latest version of Origin at www.origin.com/download (and make sure you have your Origin account ready as well).
Close the origin client and go directly to you origin folder C:\Program Files\Origin Games. Run the origin.exe in this folder with a rightclick -> run as administrator. Under the "Origin" tab, redeem your Dead Space III game and install it via the Origin client under "My Games".
Please keep us updated if that workaround was able to solve your issue!
Basti
