Formatting a hard drive along with the install of a new OS is the best option. The vast majority of operating system installations provide a "format" option as part of the installation process.
Those old CD games that have been sitting on your shelf for eternity? Linux can run them.
Installing an SSD is one of the most straightforward upgrades you can do to your PC — the only one with fewer steps is installing new memory. That makes it a great way to try out upgrading your PC by ...