I used a freeware utility called "savepart" to save the partition from
the old drive and restore it to the new drive. I've used it many times
in the past on all versions of Windows, but I think I always restored
to the same size partition. I think that's the problem. All of the
files are fine and I've inspected the boot sector, but I don't see
anything wrong.

I'm going to try one more thing. I'll install XP, save the boot sector
it creates and compare it to the boot sector after I restore the
partition. My theory is that when I restore the partition the boot
sector for the partition (not the MBR) is getting overwritten. I
thought the "fixboot" command was supposed to address this?

I don't know if it matters, but I'm using FAT32