While you can gain a surface understanding of the Bible without Him, for understanding within your spirit, you will need His help. And the Holy Spirit of God is capable of giving you an understanding that you couldn't get from the finest theological seminary in the country!
Jesus himself tells us that the Father would send a Counselor (some translations will say a Comforter) who will teach us all things and remind us of everything Jesus said to us.
Take a look at John 14:15-31 which is Jesus' teaching on the Holy Spirit, his coming and his role.
Eph. 1:13-14 lets you know that the Holy Spirit was given to us as a deposit guaranteeing our inheritance. In other words, He remains with you! So He is always available to teach.
So before you do anything else, when you settle down to study your Bible, first and foremost, pray and ask the Holy Spirit to give you insight and understanding.
He is capable more than anyone of being able to guide us into all truth!