"Error Loading OS" boot failure please help

[thephilosophizer]

I can't figure out what is wrong. I didn't change anything recently, there were no power surges, but I turned my computer off (normal shutdown from windows). And when I rebooted about an hour later I get the response "ERROR LOADING OS".
So far I have tried rearranging the boot (to the point of having the hard be the only thing on there). I have tried unplugging all other drives, I have tried going into the windows repair console but everything comes up normal when running chkdsk, and when I run fixboot nothing happens. The drive does show, and it says the correct amount of free/used space.
I can't lose the data I have on that drive, I will do next to anything to keep that data. Currently I am installing windows onto a different hard drive and seeing if I can access the data on the first drive (I had recently started a new backup system, which first involved deleting partitions off my backup drive, so I currently have nothing backed up, I was going to do that last night, but my comp was dead.)

[Rootstonian]

Has all the signs of the HD going bad; you're doing the right thing by reinstalling OS on another drive. Then hook-up the "bad" drive as slave or cable select (if IDE) or put it into an external case and try to salvage the data.

Good Luck!