What does this mean:
XP won't boot and I can't boot from the XP cd to maybe try and repair damages.
Does it boot, then fail ???. I'm presuming so - if so the MBR is o.k., and recovery console probably won't help.
If you can't boot the CD, you can't do that anyway - I'm confused.
As for mounting and (hopefully) recovering - Knoppix. Always think Knoppix.
Just remember it mounts everything R/O, so you'll have to remount the target directory to be able to save your data.