I'm not a complete idiot. The mentioned size IS missing. The disk, like an above poster mentioned isn't 80 GB in reality, which is why Windows lists it as 75 GB.
I'll try the software you suggested, thanks
Pagefile.sys : 12 GB, even though I have the pagefile turned off completely.
Hiberfile.sys: 9 GB - I don't user hibernate, my computer can boot in 20 seconds anyway.
Are they both safe to delete?
Apparently the pagefile had turned itself back on, and to get rid of the hiberfil.sys I wrote powercfg.exe -h off in the commando prompt, problem solved