I have a pretty big problem: I can't attack or use abilities.

I've been able to play Smite up to account level 10 and I've had no problems so far. This last match I played, I was unable to use any of my abilities or even auto attack. I can buy items from the item store and I can even toggle sprint if I purchase it, but I can't attack. I've tried selecting random Gods and I can't use any of their abilities. Is there a fix for this? I've even tried re-installing the game but that didn't help. I also created a new account but the problem persisted to that account as well.

That happens every now and then, but I've never heard of it persisting across games or even with redownloads. That is exceptionally odd. Have you restarted your computer since this episode or has this all been in one usage session?

After I re-installed the game and the problem was still there, I tried a restart as well. I still have the same problem, on both accounts.

This is really weird. Sometimes the problem would be a stuck spacebar, as jumping sometimes doens't register as finished, and you cannot do anything while jumping. However, I"m sure you'd have noticed a stuck spacebar, especially as you went through typing this post.

I'd suggest asking hirez support. I have never heard of this problem persisting.

Update: The fire command in the key binding menu was bound to XboxTypeS_RightTrigger. I had somehow removed mouse1. All is good.

Thanks for your help Raventhor.