Windows 7: NTLDR is missing

I have Windows XP installed and booted the Windows 7 Professiional install disk. I selected setup, then Custom, then partition 0 which was an empty formatted separate hard drive. Partition 1 was the Windows XP installation. Windows 7 installed fine and appears to run well.
However, Window 7 will not boot unless the installation disk is in the dvd drive. If the disk is out of the drive, I get an error message "NTLDR is missing". If BIOS is set to boot the XP drive, there is no dual boot option but XP boots just fine. If BIOS is set to the 7 drive, there is also no dual boot option and 7 only boots without the "NTLDR" if the installation disk is in place.
How can I fix it so I get a dual boot menu at boot up and stop the "NTLDR" error?

Boot into Windows 7 DVD Repair console, see if it discovers an installation to repair, click through to recovery tools list to run Startup Repair up to 3 separate times to recover the MBR into Windows 7.

This will likely make Windows 7 booted independently, however XP should still hold its abiility to boot, so you can try using a BIOS managed Dual Boot by setting one HD as default first to boot in BIOS setup, then if you want to access other HD use the F-key given for Boot menu on BIOS boot screen.

If you want a Windows-managed Dual Boot, which makes the drives interdependent upon each other and harder to extricate, install EasyBCD 2.0 beta in Windows 7 after doing quick registration to use beta, then add XP on its Add/Remove tab.

If there are any further problems, post back a screenshot of full Disk Mgmt drive map and EasyBCD listings using Snipping Tool in Start Menu, attach file using paper clip in reply box.

I used the setup disk to run startup Repair and at first it showed no os to repair. The second time it found Windows 7 and the post run log says it boots fine. It still required the setup disk to be in the CDROM for it to correctly boot into Windows 7 without the "ntldr is missing" message. Bcdedit showed no entry for Windows Legacy OS Loader. I figured out how to add the following line.
identifier {legacy}
device partition=E:
path \ntldr
discription Windows XP
Under A Windows 7 boot (with the disk in the CDROM) I get a menu with two choices but Windows XP choice simply reboots the computer. Again under Windows 7, C: drive is where 7 is, D: drive is a data only drive and E: is the drive where Windows XP is located.
Any thoughts?

Did you click through to Recovery Tools to run Startup Repair at least 3 separate times with reboots?

Startup repair can fix only one thing at a time.
It will usually take a minimum of three complete times to fix problems like yours, rebooting after each run.
As Greg recommends, run startup repair three complete times, rebooting each time.

If you still have problems, post a screen shot of disk management. This will let us know what needs to be done.

How to Post a Screenshot in Seven Forums

Thanks for the suggestions. I did Startup Repair 4 times with no change in the error message "NTLDR is missing" I copied NTLDR and NTDetect.com to C:\ of the Windows 7 hard drive with only a new batch of error messages.
This problem started when I took a hard drive with an old installation of Windows XP on it and reformated it using my current installation of Windows XP. I used the Windows 7 install disk, selected Custom install and selected partition0(the newly formatted hard drive) where partition1 was my currently installed Windows XP on a second hard drive. Apparently, that is my mistake. I used the Windows 7 "advanced disk options" to remove the partition (partition0) and reinstalled Windows 7 to the "unallocated" drive. It now works fine.
I have the dual boot menu and everything works as it should. Apparedly formatting with XP still leaves something in the boot sector. Anyway, problem fixed. Thanks!

Xp uses a slightly different partition table in formatting as well.