when iam trying to install grub in ubuntu my connectivtity is lost and grub is not installed and ubuntu is also not opening even through my windows 8 boot loader

OmgUbuntu has a guide called "sticking it to Grub" which may help.

Have you also tried YouTube videos for guidance?

Actually iam getting a command window after clicking f9 and the command window it is displaying the following
     Gnu grub version 2.02~beta2-9ubuntu1and minimal bash-like line editing is supported.

Now can you please tell me what actually the problem is

How is your system set up?
What is the layout of the partitions on your hard disk?
In what sequence have you tried installing Windows and Ubuntu?
Was windows pre-installed?
What do you mean by "connectivity is lost"?

From inside Ubuntu what is the output of the terminal commands
df -h
sudo fdisk -l
sudo sgdisk -p /dev/sda

hi manfred Hampl keerthi is my collegue his system was initially with windows and he dual booted it with ubuntu 14.04LTS
one week back when he was installing(updating) grub in ubuntu the net connectivity is lost and when he open the computer the next time the stated error is coming and he was unable to open ubuntu but he was able to open windows 8. i donot know much about how to solve this problem.but i want to explain what was happened clearly.

Hii hampl as it was mentioned in the earlier post by aditya that windows is already pre installed and my partions are windows(c) about 808 gb ntfs and recovery about 22 gb oem partition and 88 gb healthy(primary partition).
    You asked me to find the output of the above mentioned commands inside the ubuntu but iam to unable to open ubuntu in my laptop to use the above commands.
      I already mentioned in my earlier post what is resulting in when iam trying to open my ubuntu.

Can you now please tell me how to solve my problem by considering my previous post

Have you tried installing Ubuntu by booting from an installation DVD or booting from an USB stick, or did you use wubi?

Wubi usually fails when used with windows 8

No i didn't try of the above mentioned.

How did you install Ubuntu?

Can you tell me if there is any way to open my ubuntu that is either from efi boot or whatever is possible.

I installed it using a pendrive as i don't have a cd drive.

Can you re-insert the pendrive from which you installed Ubuntu, reboot your system and select that the computer is booting from that pendrive; at the moment that you are asked, select "Try Ubuntu without installing", open a terminal window and finally issue the commands that I asked previously?

df -h
sudo fdisk -l
sudo sgdisk -p /dev/sda
sudo sgdisk -p /dev/sdb

I need some time to answer your question because iam now downloading the ubuntu iso file and need to boot my pendrive which takes some time but i hope the solution provided by you is correct because the almost the same solution is provided in the net but with a slight modification

First i thank Hampl,Actionparsnip and Aditya for helping me to start solving the problem and i finally solved the problem and the solution to my problem is provided in the below link.Please refer to the below link if anyone has come across the same problem.

                                http://itsfoss.com/fix-minimal-bash-line-editing-supported-grub-error-linux/ is the required link for solving the grub error that i came across.