Show all work with proper formulas

A 5.00kg block on a flat smooth surface is connected to a light horizontal spring ( k= 100N/m ). The spring is initially at its equilibrium position, and the block is at rest. A student then comes along and pulls the block horizontally and stretches the spring out. When she stretches the spring out by 37.0cm, she holds the block there at rest. How much work ( J ) did the spring do on the block? Give answer to two places to the right of the decimal