re: non-destructive reinstall
Encountering an error that is identified as commonly related to problems with the boot device after a failed non-destructive reinstall are almost always a direct result of that failed reinstall. Think about it -- with a non-destructive reinstall, you're trying to overwrite the boot data on your boot device. If something goes wrong with that, you'll have a boot device problem.
Basically, the attempted reinstall screwed up the boot device somehow. That's how it looks to me.
Now . . . why you were having problems in the first place, and why the reinstall didn't work, is another matter entirely. There are a number of possibilities for why both things might have happened, but a possible single explanation for both is a degraded power supply. If you are not using an uninterruptible power supply that provides conditioned power, fluctuations in the electricity you get from the wall socket may well have degraded the integrity of your power supply unit. This, in turn, then provides fluctuating power to the rest of the system, degrading the integrity (the "health", if you will) of the various components of your computer.
This sort of thing leads to weird, intermittent problems that are difficult to diagnose, and it may be that some of the problems you were having with the system in the first place were a result of that, and the failure of the reinstall may have occurred because of some problems with the hard drive electronics, RAM, CD drive electronics, or some other part that doesn't spring immediately to mind at the moment.
That may not be your problem, but it's a possibility. If you have someone handy that knows his way around a multimeter, you may want to have your power supply checked out. Don't try it yourself unless you know what you're doing, though, so you don't electrocute yourself.
