If you’ve been using PCs for a decade or more, you might be familiar with performance-boosting programs like CCleaner that claim to clean, optimize, and maintain your PC. While some of the functions that these programs perform can be done by the user using built-in Windows tools, others are simply unnecessary and even dangerous on modern systems. If you’re using an ancient PC, you might get some mileage out of “cleaning the memory” or removing junk files, but most people should stay away from these placebos.