Is there software that tells you where things using up a lot of memory are on your drive?

Got a slave drive to make a back up on. I backed up all the folders under Users, such as Documents, Pictures, Music, Movies, Games. And then deleted all their contents. But my main drive still shows 167 GB free of 288 GB. I already deleted everything I know of, WTF? The Windows System folder and Program files are roughly 25GB. Still that doesn't explain why half of my drive has its disk space used up. I don't know what's using up the rest of the disk space. How can I find out?