When I try to open my game, it says "The operation was canceled by the user" eve

I bought Star Wars Battlefront II four days ago and ever since I have been having problems with it. (Some of these issues may have been my fault) First, I downloaded the game and it worked fine, after about an hour of playing, I closed it. I originally didn't have enough space on my C drive, so I moved the game along with Steam to my new external hard drive. I opened the game the day after and realized it wasn't working. That's when the text came up. I uninstalled Steam and installed it again. (Now I installed Steam in my main C drive because I figured that was the problem.) I installed the game again to see it still was not working. I have now installed the game three times and it still doesn't open. Please help

(I have both Steam and my games on the main C drive)