Not a day goes by where I don't receive a question as to why this or that happens on the computer and in most cases the answer is as simple as performing a re-boot and you are good to go. Of course
performing things like CCLEANER is always a good idea, especially if you do start to see strange things occurring but in most cases a simple re-boot will refresh the onboard memory/cache, repairing whatever anomalies you were having.