Are demons responsible for everything wrong in our life?

Absolutely not! Part of our teaching process is to show the demonic realm affects our soul (mind/memory/emotions). We also have a free will that God does not typically violate and we must take responsibility for our choices and decisions. The reality is that many people are powerless to get victory because they do not understand that demonic torment is behind their problem and when they are free they are better able to follow in the leading of the Holy Spirit as they purpose their will after Him.