Q: I have 79 gb in other

There seems to be a bug in Yosemite with that display,  Reindex Spotlight and that may correct it:

https://support.apple.com/en-us/HT201716

Here is the definition of OTHER:

https://support.apple.com/en-us/HT202867

Do not get obsessed by the name of the category.

Ciao.

Go to the root of your Macintosh HD and view it as a list. Then do command-j and check Calculate All Sizes. It will take a while, but you will see what folder sizes are.

Since the storage display in system preferences tells you nothing about the files or folder that are using the disk space plus it is notorious about putting the wrong files in category, it is basically worth less.

If you truly wish to fix this problem, I suggest that you download and install OmniDiskSweeper. When you run it it will tell you the files and folders that using the most dick space. With that information you should be able to solver problem.