No, unlike God, Satan hasn't always existed, nor is he all-powerful and all-knowing the way God is. And someday, every power he does possess will be taken from him, and he will be cast forever "into the eternal fire prepared for the devil and his angels" (Matthew 25:41).
The Bible doesn't answer all our questions about the devil, and we must be careful not to go beyond what God has told us in His Word. Nevertheless, the Bible indicates that originally Satan was one of the angels God created to serve Him. But Satan became envious of God, and decided to rebel against God and try to take His place.
His rebellion was unsuccessful, however, and he was thrown out of heaven: "How you have fallen from heaven... You have been cast down to the earth" (Isaiah 14:12).
Never doubt Satan's reality–and never doubt His ability to deceive us or bring evil to the human race. His single goal is to block God's plans, and he will do everything he can to keep us from God. Jesus rightly called him "a liar and the father of lies" (John 8:44).
But listen: Satan is a defeated foe! By His death and resurrection Christ overcame Satan's power, and someday the final battle will be fought and Satan will be defeated forever. Are you on the winning side? You can be, by giving your life to Christ.