Why do ext2 Files Become Corrupt so Often?

bnagel asks: "I always properly halt my computer. Twice in the past month, when I have booted back into Linux, a number of files are corrupt, and I have to reformat and reinstall. The files get an invalid userid and date and when I try to execute one, bash says that it was not found. I'm using Caldera 2.3. I can't think of using another OS, but if this becomes a monthly ritual, I might have to. Can anyone explain this ext2 phenomenon?" An odd problem which I have not experienced before, and I'm less careful with my HDs. Does anyone have any helpful information?