C Cleaner

CCleaner is a computer cleaning and optimization utility originally developed by Piriform and now owned by Avast. First launched in 2004, it's one of the longest-running system cleaners still in active use, and remains a go-to tool for anyone whose PC has slowed down under years of accumulated clutter.

At its core, CCleaner scans for potentially unwanted temporary files and invalid Windows Registry entries, then removes them to free up disk space and reduce the small errors that can accumulate over time. The one-click cleaning mode is built for beginners who just want a faster PC without digging through settings, while advanced users can dig into granular controls for startup programs, browser data, and more.

With millions of downloads over nearly two decades, CCleaner has built a reputation as an easy entry point into PC maintenance - useful both as a one-time deep clean after a fresh install and as a recurring tool to keep a Windows machine running smoothly.