Solve Ntldr missing, Cltrl+Alt+Del to restart type error in XP

Many times due to instant turnoff or other causes the OS gets corrupted mostly showing the error
"NTLDR missing" or "Press any key to Restart " or "Press Ctlr+Alt+Del" type of errors.Sometimes our pc takes much time to load this could be solved by following this steps:-

1. Enter the bios by pressing "del or F10", change the boot device options first boot device: CDROM and second boot device: HDD.
2. Insert a Windows Xp cd and press any key at the prompt "Press any key to boot from CD/DVD".
3. After Xp loads the first window appears which asks for " Enter to Continue" , "R to Repair" and "F3 to quit". Here press "R".
4. A dos prompt loads asking "which windows installation...." press "1", press "Enter" or the admin password if any.
5. Now prompt is C:/Windows 
6. type "fixboot" it asks "due you want to write a new boot sector" press "enter" and or "Y".
7. Reboot your Computer.