Returning to the fold

I was attending Oregon Tech in 2012 and I was in the early stages of my coding education. I had to bail on it when my kids were born so that we could live on. Anyway, I am getting to a point where I can jump back in, but I don't have my copy of Visual Studio anymore, and I would like to refresh my skills and memory of what I was able to learn, so that I don't fall flat on my face when I do get back in to class.

I have all of my projects left over, but the VS 2015 Express that I downloaded can't open any of them.

Any suggestions for a code editor that I could get a hold of for free/cheap?