After Fixing My Computer

Today I opened my computer and i noticed that my computer is slower than before. It usually happens when ur computer is infected by evil viruses or your C Drive is almost full. So I checked my Drive C and D and I saw only 10 GBs are free now.. It was unbelivable.. Since when it was getting full? What have I downloaded? (NOT PORN!!) Soo I checked my D Drive file and I was confused because the files were not arranged and  mixed.. LOL and i noticed I have a lot of program installers, Movies and games. And still I didn't know what things that are mostly occupying.. Soo i checked the properties of my Game File.. And I saw three digits of GBs.... And I was amazed at myslef.. Where the hell are they from?.. So I  started deleting games that are not interesting anymore or already have finished before. and the size of the file got smaller  and smaller and reached 80GBs.. those 80GBs games are undeletable haha some, I haven't tried yet or my favorites. Thankfully my computer was highly proteced from viruses.. so the problem was the occupation of the files in my drives.. I think I'll really need to buy a external hard drive to have more space in my computer because everytime I delete my games.. it feels like.. I'm throwing my treasures that I have collected.. well I'm glad because now my computer is cleaned and my files are properly arranged :DD