To dual boot Ubuntu with windows 7, 8, 8.1 or 10;
Follow the following steps:
Download mini tool partition.( its free of cost and better than the disk management system of windows OS)
open Mini tool partition and create a 25-30 GB of allocated partition.i suggest you to take 25 GB of partition space.
Download Universal USB installer(this software is also free of cost)
Connect your USB drive to your computer and format it.
open Universal USB installer and select the Linux family and mount the Ubuntu.ISO image to the CD or USB drive.
restart your computer.
ass soon as you restart the device you will get a message on the screen
example: a) press enter to interrupt normal setup,
b) press Del to enter into boot menu,
c) or some other similar message.
after entering into the boot menu select the 'mass storage device from the list and hit enter'
Your Ubuntu setup screen will prompt select "install Ubuntu" from the list or "graphic install (if available)"
Immediately nothing will happen and take patience as this will take 2-5 minutes to start the setup after selecting the install option so please wait for the setup to run and do not eject the the USB drive from the computer. Many people think that their system did hang but actually it is not like what they think because setup take 2-5 approx minutes to run so don't worry and wait for a while it will definitely run after some time.
after all setup will start and follow the instructions.
the setup will ask you to select a choice out of two/three
a) erase disk and install Ubuntu,
b) Something else.
select b) something else and the setup will take you to the disk selection menu.
14.If you took the the partition of 25 GB double-click on the free space and then select "swap area" option from the list and enter the size: 3072 MB and press continue.
Now again double click the free space partition and select the "ext4" and in the second box select the "/" option from the list and enter the size: 7168 MB
follow the same procedure again and make two more partition of "/boot" and "/home" both or each should have the size: 7168 MB
Press continue. If you are asked to provide a host name the just type "ubuntu" and proceed further.
The installation process of Ubuntu is much easy as compared to other distributions of Linux. But if still you you have any doubt or error while installing you can contact me or send me a mail at: mailrizvi786rediffmail.com