directories renamed to “dir00001 etc.”

We have one machine with ME on it and last week it crashed (while I was out of the office), so who knows what happened. Anyway, it would only boot to DOS and would not recognize any other directories. When I did a “dir” all of the directories were renamed to things like dir00001, dir00002 etc.
Does anyone have any clue as to what might have happened. I was going to do an fdisk and start from scratch myself but I chose to send it out to someone with more experience than me. But I still would like to gain some knowledge from this.
Thanks,
Rick