Dean, I neither profess to be a Biblical student, nor a diviner of what the Bible means to mankind. I do read the Bible and have taken many Bible Study courses which have led me to believe that the New Testament did not invalidate the Old Testament, but did fulfill it.
The Old Testament tells of God’s marvelous Creation of earth, man ,and all there is of this world. It also gives us insight into how God, our Creator did all he could to get his creations to live lives of peace and harmony with all of His creation. He gave them prophets, judges, kings and scripture. However, because mankind was too fragile and too human to understand or obey even after he had destroyed all but a small number of his beloved creation, He had to send His Son as the sacrificial Lamb to save us all.
Thus the New Testament gives us the beginning of wisdom and the life and message of Jesus Christ, the Savior. This became the fulfillment of the Old Testament. Jesus completed the role of the Beginning and became the Omega-the Word made flesh-the Word Personified: Father-Son-Holy Spirit=the Triune God! Man was saved through Jesus, whose life was explained in the New Testament and is the fulfillment of the Old Testament.
No, the Old Testament was not invalidated; it is given to us to show us the only way to salvation. God bless you and may His Grace always be in your life.