Sealing concrete cracks and joints with a quality sealant will help to prevent future settling and cracking. Professional grade sealants are designed with great adhesion properties and they will remain flexible inbelow freezing temperatures.
Although many "Do It Yourself" grade sealants are readily available where other construction supplies are sold, these sealants rarely last. They often become rigid and break within a couple months.
Epoxy injection is a great technology that utilizes high solids epoxies to literally glue your poured foundation walls back together. These epoxies have two key features; they are at about the consistency of water so they can flow into even the smallest cracks and they are composed of high solids to offer the greatest bonding strength. If your poured basement walls are cracking, epoxy injection will stop the spread of those cracks and help to ensure your foundation will last for decades to come.