Problem solving is the mental process we follow when we have a goal but can't immediately understand how to achieve it. It's a process that depends on us - how we perceive a problem, what we know about it, and the end-state we want to reach. Solving a problem involves a number of cognitive activities:
ascertaining what the problem really is.
identifying the true causes of your problem and the opportunities for reaching your goal
generating creative solutions to the problem
evaluating and choosing the best solution, and
implementing the best solution, then monitoring your actions and their results to ensure the problem is solved successfully