When the available space in volume C is becoming less and less or the system runs slower and slower, you don't have to reinstall Windows in order to solve all problems. Instead, before doing that you can try to use Auslogics Windows Slimmer to give your Windows a full trim (to save space and boost performance) and look at the effect.

Windows Update Clean Tool (WUCT for short) is a very significant Windows system useless files automatic and powerful cleaning tool, with which you can clean up these kinds of system junk files:Update Backup File, System Log, Installer CLR Cache, Manifest Cache, Windows Temp File and Defender Scan Cache and more.