my pc wont start to windows and it wont let me reformat it?

[kcarter]

before this problem, my pc would keep on restarting on its own. so i thought of formatting it.

the first time i tried, it let me do the formatting but it didnt let me finish. then the next time i tried formatting, it already says " a problem has been detected and windows has been shut down to prevent damage to your computer" and something like " setupdd.sys caused this"

then when i try to start without the windows xp cd, it wont, and it'd just say " NTLDR is missing ; press ctrl+alt+del to restart"

please help me thanks
i cant go to safe mode either, it just does the first part of the start up until
boot from cd:
boot from cd:
then it displays cannot find NTLFS
press ctrl alt del to restart
NTLDR i mean