Neither of the links above will let me install on my Hard Drive.
Kim,
I wonder if your internal drive is "corrupted/damaged", and can be resurrected/fixed by software? Do you happen to have either TechTool Pro or Disk Warrior? If not, then your only alternative is to try Disk Utility and see if that will help. Given that you have a backup, it should be OK to try it.
I do, though, have one question. How did you upgrade to Sierra, OS 10.12? Ddi you do an "upgrade in place", ie, run the upgrade "on top of" whatever prior OS you were using, or did you do a clean installation of OS 10.12 (now up to OS 10.12.1, and there is already a second beta of OS 10.12.2)?
Additionally, do you still have the file "Install macOS Sierra" some place?
In any event, what you need to do is run Disk Utility in an "isolated" manner. To do that, you need to boot to the (hidden) Recovery HD partition on your drive. This link shows how to boot to it, and what the capabilities are:
https://support.apple.com/en-us/HT201314
So, after you boot to that partition, you would select 4th choice, Disk Utility, on the menu, and then attempt to Repair your internal drive. It would be good to do the repair at both the Volume (ie, top) and Partition (ie, secondary) levels.
Also, you should download, install, and run the excellent freeware program Onyx. You can get it from here:
http://www.titanium.free.fr/onyx.html
You MUST get Version 3.2.1 (the first one on the list), given that you are using Sierra. One of the features of Onyx is that it can Repair Permissions. Even since El Capitan, the Mac OS supposedly takes care of that, but I see just the opposite. Every time I do my weekly disk cleanup/maintenance/repair, and backup, tasks, I always run Onyx first, and it always Repairs Permissions. And in fact, I need to run it at least twice (this is true for both of my Macs). It also has some useful clean up features.
Purchasing and installing Office 2016 will not resolve your "Entourage" issues, as you need to do the repairs first.