GRUB uses a "device map" to locate its "Stage 2" files. Your new partition may have changed the "real" device map from the one GRUB has installed in the boot sector.
However, if Knoppix can't find you Linux installation, XP may have "decided" that you weren't really
serious about Linux, and "reused" your Linux space.
Suggestion: Boot Knoppix and create a GRUB boot floppy (Here
's a brief description of how it can be done I wrote a while ago. If you use mkfs -t vfat
instead of mke2fs
, you should be able to edit the floppy from XP.) Then see if you can change (if it doesn't boot) the root
line so it does work.
If you can get Fedora to boot, see if a "grub-install
" fixes your problem.