NTLDR is missing

When you face this error, do the following:

1. Boot from WinXP boot CD
2. Choose R to run the Recovery Console
3. Copy NTLDR & NDETECT.COM from cdrom:\I386 to C:\
   
4. Check if BOOT.INI is missing by using the DIR command
5. If missing use the BOOTCFG /REBUILD to add OS to new BOOT.INI
6. If not missing, just reboot and voila!

The normal BOOT.INI file contains the following entries:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /NoExecute=OptIn /fastdetect


You can change the /NoExecute to use AlwaysOff and add /NOPAE. Read the reason for the change as documented in this entry.