OK, that wasn't the problem. That box wasn't checked.
My CDrive didn't die, and until it does something that Seagate recognizes as a problem, they won't give me a new one.
So, moving on.
The reason the RAM is the way it is with 16 G is because it's two matched sets of 4G sticks---they came in pairs, I bought two pair.
Now, it's showing that I have 16G installed, but it says I only have 6.9 G usable? What's all that about??
This RAM issue is driving me crazy.