Re: my mac pro doesn't boot u...
I reformatted, replaced all of my content using my timemachine snapshot and got back on my feet for a couple weeks.
Interestingly, it's not the end of my journey just yet. Just yesterday (or was it the day before) I started to experience a periodic "spinning beachball of death" where my machine simply decided to stop for a while. It only seemed to happen when I was using applications (like chrome or firefox), but fortunately system tools (specifically timemachine) seemed to work. I made a current backup, and created a new user profile in which all of the programs seem to work like a champ with no lockup.
I now need to transfer documents from my other profile, but I want to be cautious to not bring over whatever the heinous things are that were locking up my machine.
Long and short of it, I was able to get past the original problem, but I wasn't out of the woods yet.
Thanks for checking in.