I'd like to preface that I'm not the best with technology in this area, so please excuse my lack of knowledge.
I have a newly built computer with an AMD Radeon R9 280x graphics card installed. For the last week and a half since it's been built, it has been running smoothly and perfectly. The game I play the most, Skyrim, has been running at Ultra High Quality. Today, quality settings have been reduced to low/medium quality. Several other games, including Borderlands and Call of Duty have been running just as poorly.
What could have changed? Could a graphics driver just "go bad" after running just fine for the past week and a half? Would it need to be reinstalled? I apologize for my lack of knowledge on the subject and if any answer or more information could be provided in layman terms, that would be greatly appreciated.