Baptism is a fundemental doctrine of the church:
Heb 6:1,2 Therefore leaving the principles of the doctrine of Christ, let us go on unto perfection; not laying again the foundation of repentance from dead works, and of faith toward God, of the doctrine of baptisms, and of laying on of hands, and of resurrection of the dead, and of eternal judgment.
Under normal circumstances baptism is followed by the laying on of hands of church elders (another fundemental doctrine)which imparts God's spirit:
2Ti 1:6 Wherefore I put thee in remembrance that thou stir up the gift of God, which is in thee by the putting on of my hands.
1Ti 4:14 Neglect not the gift that is in thee, which was given thee by prophecy, with the laying on of the hands of the presbytery
Above Paul describe HOW Timothy got the gift of God, the Holy spirit.
Act 19:5 When they heard this, they were baptized in the name of the Lord Jesus.
Act 19:6 And when Paul had laid his hands upon them, the Holy Ghost came on them; and they spake with tongues, and prophesied.
Above is an example of people who were baptized, but not in the name of Christ. They didn't get God's spirit until Paul laid hands on them and asked God to give it to them.
Act 8:18 And when Simon saw that through laying on of the apostles' hands the Holy Ghost was given, he offered them money,
Act 8:19 Saying, Give me also this power, that on whomsoever I lay hands, he may receive the Holy Ghost.
Another example above. Simon saw how the Holy Ghost was given and tried to buy the power.
There are extraordinary occurrences where people get God's spirit WITHOUT having hands laid on them...but it only happened with the original jewish converts (Acts 2) and with the original gentile converts (Acts 10).
So I would say that if one hasn't been baptized then they have not obeyed God's instructions for receiving the holy spirit. That's not to say that everyone baptized and having hands laid on them DOES have God's spirit though.