Hi,
Something to do once you have a running Xp system.
Go into C:\ and unhide hidden and hidden System files.
select and copy files:
boot.ini
NTLDR
NTdetect.com
And paste them into a floppy.
Boot up onto the floppy if any of these are corrupted and your up and runnign again.
I recently tried to put Linux first on a HD then XP (which is not adviced) and as you install XP into the second partition it is beyond the boot area so these files were put onto the first HD track and so when I installed the Linux Grub it over wrote these and XP wouldnt boot, but this floppy got me running again an then I copy pasted them back into C:\ and its OK again.
So they are handy to have saved.