Start by restarting the computer — a real restart, not just closing the lid. This clears memory that’s tied up by background programs and lets any pending updates finish, and it fixes more problems than people expect. After that, check how much storage space you have left, since a nearly-full hard drive is one of the most common causes of a sluggish computer. If it’s still slow afterward, that’s a good sign it’s time to have someone take a closer look.