The Law of sin and death is the entire OT Law.
It reveals sin and demands death per the previous chapter.
In Romans 7:25-8:2, Paul contrasted the Law of God with the law of sin and contrasted the Law of the Spirit of life with the law of sin and death, so he equated the Law of God with the Law of the Spirit, which straightforwardly makes sense because the Spirit is God. The Law of Moses was given by God (Deuteronomy 5:31-33), so it is the Law of God and it was referred to as being the Law of God in verses like Nehemiah 8:1-8, Ezra 7:6-12, and Luke 2:22-23. In other words, the Law of Moses is the Law of the Spirit of Life.
Was the old testament law your schoolmaster to bring you to Christ, or was the law of the Spirit the schoolmaster to bring you to Christ?
Are you no longer under the OT schoolmaster? Or is the schoolmaster the Spirit you are no longer under?
In Matthew 7:23, Jesus said that he would tell those who are workers of lawlessness to depart from him because he never knew them, so God's law brings us to Christ because it teaches us how to know him, but does not lead us to Christ so that we can then reject what he taught and go back to living in sin. Someone who disregarded everything that their schoolmaster taught them after they graduated would be missing the whole point of a schoolmaster.
In Galatians 3:16-19, a newer covenant does not nullify the promise of an older covenant that has already been ratified, so the New Covenant does not nullify our need to obey God's law. Likewise, in Galatians 3:25-29, every aspect of being children of God, in Christ, through faith, being children of Abraham, and heirs of the promise is all directly connected to living in obedience to God's law. In 1 John 3:4-10, those who do not practice righteousness in obedience to God's law are not children of God, in 1 John 2:6, those who are in Christ are obligated to walk in the same way he walked, in Romans 3:31, our faith upholds God's law, and in John 8:39, Jesus said that if they were children of Abraham, then they would be doing the same words as him, and the works that they should be doing were in obedience to God's law.
Did Abraham have the OT Law?
Indeed, in Genesis 18:19, it says that God knew Abraham that he would teach his children and those of his household to walk in His way by doing righteousness and justice that the Lord may bring to him all that he has promised. In Genesis 26:4-5, God will multiply Abraham's children as the stars in the heaven, to his children He will give all of these lands, and through his children all of the nations of the earth will be blessed because he heard God's voice and guarded His charge, His statutes, His commandments, and His laws. In Deuteronomy 30:16, if the children of Abraham love the Lord their God with all of their heart by walking in His way in obedience to His commandments, statutes, and laws, then they will live and multiply and God will bless them non the land that they go to possess. So the promise was made to Abraham because he walked in God's way in obedience to His law, he taught his children and his household to do that, and because they did that in obedience to the Law of Moses.