How To Troubleshoot boot partition in Linux

How To Troubleshoot when /boot partition value has changed

or

To Troubleshoot Error 15/17

Case I:--

1.    Restart System and intrupt booting by pressing any key

2.    Press E on redhat linux title to edit

3.    Again Press E to edit parttion value

4.    After Editing Press B to boot machine

NOTE:- Follow Above Steps if we know /boot partition value

Case II:--

1.    IF we don't know about /boot partition value:

2.    Boot System with Linux DVD.

3.    Select Rescue Mode Installation

4.    Select Language, Keyboard type and Time etc.

5.    Then Select media device where OS image already exits

6.    Contd as a root

7.    select shell

8.    Then run following commands

                         #chroot /mnt/sysimage

                   #mount or fdisk -l     (To check /boot partition)

9.    vi /etc/grub.conf

                   and change partition value and save file

     10. after exit Reboot System