It's been a while since ive cleaned my pc so now i want a mass cleaning. what else can i do besides CCleaner?
Defrag, uninstall as much apps as you can, remove unneeded startup entries, delete old system restore points if there are such... but you probably have done these already.
"I like to tank pugs. It toughens me up and makes my skin as thick as my armour." - mouseno4
What everyone else has posted plus checking for updated drivers.
Or you can do what I do and every 6 months just format your PC and start from scratch
buy an SSD, this will give you the biggest speed boost, as currently the major holdback is storage