The problem is that all Adobe installers install the original release version. So, when you re-installed CS5, you went back to Photoshop 12.0 and ACR 6.0, which do not support your raw files from whatever camera make and model.
The inability to update through the Adobe auto updater is not your fault at all, and it has nothing to do with your machine, your OS or your Photoshop install.
This one is very easy to explain—and solve.
The Adobe updater in CS5 and earlier versions of Photoshop was and remains a totally useless, unreliable piece of cr@p. The hapless Adobe installer and updater team in India did not get their act together until version CS6, then went back to their usual incompetence with Photoshop CC and CC2014.
There's absolutely nothing wrong with your Photoshop installation and you are doing nothing wrong yourself.
What you're going to have to do, is locate, download and install the update you need yourself, following the instructions on the download page to the letter.
Here's the Windows version of the update:
and for Mac:
After that locate download and install the ACR 8.7.plug-in. I'd look for the link for you if you had specified your platform, Mac or Win. As it is, I already did too much of your legwork for you with the two links I cited above.
Thank you so much. I probably went through this about three years ago when I bought the software and I just don't remember. You know, you spend hundreds of dollars on software and you expect it to work correctly!