I have an arduino uno board running the auger on a pellet stove, but I need to modify the programming on it and the computer I was using was formatted. I was wondering if there was a way to get the code from the board itself to make some tweeks.
No, you will never get the C++ code back. There is a way to get the machine code back, but it mostly won't help you.
When I saw the title I was going to suggest reading this Thread. But it would not be effective against formatting a hard drive and having no backup copies.
...R