Ok...so a new installation is created along with every iteration of the program. How can I download the new installation without having to purchase the game again? I only get an option to upgrade. Thanx for any help.

I purchased the game to play on my laptop when I have some free time @ work. I downloaded the installation on my desktop and installed it on my laptop.I NEVER use my laptop to connect to the internet so I can't download any updates. Are the updates available via download from outside Factorio.