Volume Disk not showing in disk managment.

I was trying to dual boot win 8 and win7(was already installed) on my laptop.During installation win8 was giving an error,that win could not update the computer's boot configuration.(See attached pic )
I googled this error and came across this post.

Boot from 7 or 8 DVD and goto Repair console > Command Prompt (Hit enter after each line)

---
diskpart
list disk
select volume x (x = being the volume number of your HDD)
clean
create partition primary
active
format fs=ntfs quick
assign
exit


Reboot and try setup again (I use this for USB drives, but they are not partitioned, I imagine this will kill all partitions on the disk and create just one new one)

After doing all this I was able to install window 8 but my 2 hard disk partition are not showing.My total hard disk is of 300 GB,but now only a single partition of 149 GB is showing.The remaining hard is not visible anywhere,not in disk management, and not even in ease-us disk partition.

What does diskpart show you from an Elevated Command Prompt? For instance, mine shows:

C:\Windows\system32>diskpart

Microsoft DiskPart version 6.2.9200

Copyright (C) 1999-2012 Microsoft Corporation.
On computer: DESKTOP

DISKPART> list volume

Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0 K DVD-ROM 0 B No Media
Volume 1 D D370_D NTFS Partition 78 GB Healthy System
Volume 2 E D370_E NTFS Partition 191 GB Healthy
Volume 3 F D370_F NTFS Partition 9 GB Healthy
Volume 4 C Win_8 NTFS Partition 119 GB Healthy Boot
Volume 5 G D370_G NTFS Partition 698 GB Healthy
Volume 6 H D370_H NTFS Partition 542 GB Healthy
Volume 7 I Win_7 NTFS Partition 78 GB Healthy
Volume 8 L Removable 0 B No Media

DISKPART> exit

Leaving DiskPart...

gregrocker said:

Since you say you were able to install Win8 please post back a Disk Mgmt screenshot: Disk Management - Post a Screen Capture Image. While there see if you can create a new Partition or Volume - Create New

If for some reason you can't boot Win8, boot into free Partition Wizard
bootable CD to post back a clear camera snap of the maximized drive map and listings. See if you can create a new Primary partition in the empty space. Partition Wizard Create Partition Video Help

Hey I did exactly as you said,and I have attached the captured image.
I can create new volume if I shrink the current one which is only 149 GB but my total hard is of 300 GB.My question is why my laptop is showing only 149 GB and where is the rest of my hard.

Your hard drive is not 300 GB, as mentioned you have 2 drives. Can you confirm this ?

Diskpart only shows the 1 drive. You probably only have 1 hard drive ( 149 GB )

If the other hard drive is not showing in the bios, it may have been knocked loose, or worse.