Does anyone have any ideas that may help?

I am working on my system and when i boot up i get this message. "NTLDR is missing" (NT loader). How can I go about fixing the problem. I am willing to format everything but I first need to get to a comand promt. This is what I have tried so far. I have removed the harddrive from the computer and installed it as a slave in another PC. This is my first problem with that. when I try to boot up with my system the computer locks up when trying to start XP. A different problem also occures when I install my harddrive in the other pc. It keeps telling my that xp did not istall correctly and asks me how i want to install. Either from normal mode or safe mode.. etc..... It doesn't matter which I chose it loops back to this message (windows did not startup correctly........................) Does anyone have any ideas want is the problem either Dios or harddrive?

please help.

thanks

i had this exact problem before - and let me tel u it is a real bad *** to fix!! if u can press f8 at startup go to the list and select safe mode, or safe with networking. then hopefuly u get ino windows. if u can do this then hopefuly u used win 2k backup utility some timew in the past, so pop the cd in with ur "system state and registry backup" and resore that bastard!! it does work i tel u that!! magic i say
problem is:
u may not have made backup, u probably cant get inot widnows? and u may not even have a cd- writer?
write back if u need more info cause there are other things i also have done to fix this problem before :-)