Whew! A moment of panic as I discovered the original image files for Kratos' right-facing sprite were missing! I have no idea where I saved them, as it was 2 years ago, but I suspect they were probably on the old hard drive from my dead system, and so backed up to some now-misplaced CD.
For a bit, I thought I was going to have to go back and redraw it all, but I was thankfully able to extract the images from the old .fla source file, so everything is OK.
Let this be a lesson to aspiring game developers - keep all your crap together and organized, even if you don't think you'll ever need it again! You may decide to port your project 2 years in the future and suddenly need all the original files again!