"NTLDR is missing" - do I have to reinstall XP to get around this and boot up?

Hello, I am getting error message "NTLDR is missing" when trying to
boot up my Dell Dimension 8250 XP box. F2 and F12 work but F8 (safe
mode) does not, at least I have not been able to get it to boot to safe
mode. Have rebooted from the XP boot disk and run chkdsk /r but this
does not solve it. Am advised by a local tech help person that only
solution will be to reinstall XP. Does anyone know of alternatives to
this? I would rather not do a full reinstall of XP if I can help it.
Thanks.

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