Troubleshooting a Buffalo Linkstation QVL 8TB

I returned from vacation and my various precautions had held up.  Everything was working (except one computer, but that's another story).  Then the next day - BOOM!  My NAS from Buffalo stopped working.  It was my primary backup device (luckily I have a secondary device and a tertiary device).
The first thing I did was to call Buffalo tech support.  The first tech was extremely helpful.  He said the best thing to do would be to upgrade the firmware on my drive.  So he told me reboot the drive, but my power switch wasn't working.  So I ended up, with the help of the tech support person, pulling the power plug in order to reboot the system.  I was finally able to upgrade the firmware and everything was working well.

 
I was very happy for all of one day.  The next day my drive was completely inaccessible.  When I called tech support, I had a different tech support person.  This person was not as helpful.  He said there was basically nothing I could do. We had tried searching with the Buffalo NAS Navigator, my drive didn't even show up.  I couldn't access it over the web interface and connecting it directly to a UNIX box (which I was told was unsupported but might work) did absolutely no good.  

So after I was told that everything on the drive was most likely lost (about 5 tb of data), the tech suggested the best course of action was to purchase a new NAS.  I had nothing to lose, so the next day I decided to pull one of the raided drives (there are 4) and see if I could read it using my external drive bay.  Once in the drive bay, windows 7 just asked if I wanted it to be treated as a writable DVD or a USB.  When I put the drive back into the NAS, it went from registering as okay (green light) to registering as not accessible (orange light).

Now I was able to access the NAS even though it had diminished capacity.

What do I do if my NAS is having problems?

In my opinion, your best bet is always going to be to contact tech support.  If this fails, as it did with me, definitely try to recover it yourself. If you have a raided configuration, pulling each drive and testing it may get you good results.