windows/root>\system32\ntoskrnl.exe. I don't have the XP CD to repair it, recovery mode
just keeps running, picking up no data.
How do I correct this to be able to try and do a non-destructive system restore?
You will need an XP CD to fix this. NTOSKrnl.exe is the system kernel. It's about as non-trivial a file as you can get. You may be able to find a Windows XP Recovery Console CD online somewhere (Ultimate Boot CD maybe) and get to a command line and run
Otherwise, you will need the XP CD to (at the very minimum) copy the file from the CD ot attempt a repair install of XP.