Thank you all for the suggestions and inputs. With all your help, I was able to successfully Install Ubuntu 14.0.4 LTS alongside Windows 7 Professional. My Laptop is Lenovo B50 80 with 4 GB RAM, 500 GB HDD preinstalled with Windows 7 Professional.
I'm summarizing what I did below, so that it may help others.
As mentioned in the question, I tried to shrink the C: Volume using Disk Management in Windows and allocated some space to install Ubuntu.
But, when I tried to install Ubuntu in the unallocated space, it was showing as unusable. (It is because Windows does not allow to create more than 4 partitions)
Finally, this is what I did :
Steps to Install Ubuntu alongside Windows 7 in Lenovo B50 80 :
The Windows has two drives/ partitions : (Windows C: and Lenovo D: ) other than the 2 hidden partitions for One Key Recovery.
The Lenovo D: is 25 GB and has Applications and Drivers folders. We can take a back up of that. ( In a flash drive or by copying it to the C: ).
I believe all the Applications and Drivers are available in the Lenovo website and it can be downloaded. So, I went ahead and deleted the D: partition. So, now there is an unallocated space of 25 GB. Ubuntu needs only 6 GB space for installation. So, 25 GB is more than enough.
But if you think you need more space allocated for Linux. You can shrink the C: upto 200 GB and it will merge with the already unallocated 25 GB. So, now you will be having a single partition of unallocated partition of 225 GBs.
Now restart the system with Live USB Ubuntu Flash Drive. Select Try Ubuntu.
After Ubuntu is loaded. Click Install Ubuntu.
The installation window opens. Select the Language. Click Next/ Continue
There will be options like "Install Ubuntu alongside Windows 7" . But in my case, Ubuntu did not detect Windows 7, so, I got only the following options:
Choose "Something Else" and click Continue. You will get the Partition screen.
Now you will be able to see all the partitions with the Windows drives and the free space of 225 GB.
Select the Free space and click + at the bottom to create a new Partition.
First, create a partition for Swap Area with 4 GB space. So, Give Size as 4096.
Choose the type of Partition as "Logical" instead of "Primary". Select "Use as" as Swap Area.
Next we can use the remaining free space for the rest of the Linux installation.
Again Select the Free Space and click + at the bottom.
Size will be having the remaining free space size by default. Choose the type of Partition as "Logical" instead of "Primary".
Select "Use as" as "Ext4 Journaling File System".
Select Mount Point as " /" .
- Choose your hard disk "/dev/sda..." for "Device for boot loader Installation" Option.
Click "Install Now". You will get a warning pop up that the two partitions you created now will be formatted.
Click Ok and continue with the Installation.
The Installation will be completed successfully and it will ask you to restart the system.
Go ahead and restart the system.
Remove the Live USB flash drive before rebooting.
The system will sometimes boot to Windows or Ubuntu. You will not get the GRUB loader.
If your system boots to Windows by default and you don't see Ubuntu. Shut down and reboot with Live USB again to Ubuntu.
In my Case, the system restarted to Ubuntu.
- Now we need to install the Boot Repair to fix the grub. So, Open the terminal and give the below commands one after the other:
sudo add-apt-repository ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair
- Boot Repair will open in GUI format. Just follow the given instructions and complete the process.
The GRUB will be successfully fixed.
- Shut down and restart the system. You will be seeing the GRUB to choose Ubuntu or Windows to boot.