Sounds similar to a hard drive failure that I had in the past. Not much you can do about it, hopefully you've backed up the data.
I wouldn't think it is a heat failure, as the computer seems to barely get running before it fails - not enough time to build up much heat. Nothing wrong with cleaning out the vents, though, and seeing if that makes a difference.
Just re-read the thread, you did backup the data... good job. I use Mozy online backup (same as Carbonite or other "cloud" programs) because I just couldn't remember to backup data on a regular basis.