NTDLR is in the root directory of your boot drive (C:)
You need a copyfrom another XP system preferably on a floppy, because some systems don't recognize the USB until they have booted.
Newer systems do...
I've had this happen a couple of times the other easy way to fix it is to pull the HDD from the "failed" computer and install the drive temporarily in another computer with the same general version of the OS, copy the file from the "good" system and reinstall the drive back in the dead one the "failed" computer will then USUALLY boot normally.
I haven't looked at the NTDLR file in Windows XP Media Center, but I know that the NTDLR from XP-Pro will not always work on a computer with
XP-Home or Vice-Versa, I don't know why...
So if you have "home" copy the NTDLR from another "Home" system, if you have "Pro" copy it from a "pro" system, etc...
On the XP-Pro SP3 I'm posting this reply from this file is 250048 bites.
I just checked and the NTDLR file on my XP-Home SP3 notebook is the same size since I updated to SP3)
So you probably won't need to format and reinstall the Operating system