What do you mean it goes directly to C: drive? It's cmd , it goes where you "tell it" to go!
Or do you have some administrator restrictions or something ?
Once the Windows XP cd loads, press the R key to go to recovery console.
Choose Windows installation (usually by pressing 1)
The password is required. If you have a password then write it, if you don't have a password then just press enter
The cmd will appear.
U have to use some commands to copy the ntldr and ntdetect from the Windows cd to the PC.
U have to type in cmd the following:
copy E:\i386\ntldr c:\ and press enter
copy E:\i386\ntdetect.com c:\ and press enter
(E if that's your cd drive, if not use your cd drive letter)
In some cases the error consists of a bad boot.ini also. If that's the case you will eventually have to edit it...
Keep in touch... Good luck!