To dual boot Windows 7 and Ubuntu. Follow the steps below: Method 1:
You can make dual boot system by using Wubi Installer
1) Go to Download | Ubuntu
and download Wubi installer then run this.
2) Specify the hard drive you wish to install it on. Remember that DO NOT erase Windows.
3) Select the amount of space you want to give to Ubuntu to use. I prefer 5GB.
4) Choose your desktop environment.
5) Choose your language.
6) Set your screenname. Remember that this cannot contain capital letters.
7) Set your password. When you have completed that press the install button and wait.
When it finishes downloading and installing Ubuntu, reboot to boot into Ubuntu. Method 2
You can also make dual boot by Native Install .
1) Burn a CD/DVD with the Ubuntu ISO through Windows.
2) Boot from the CD/DVD when you start up your computer.
3) Press the up button the moment something appears on that screen and select a language.
4) Choose the option 'Try ubuntu without installing'.
5) When the desktop appears double click the icon on the desktop called 'Install Ubuntu'.
6) At the time of installation, select your language and press the forward button.
7) On this screen choose the options you want. Hit the forward button again.
Next select the 'specify partitions' option and click forward.
9) Here as you can see we already have some unallocated space, click it and select the 'Add' button.
10) A window pop up, make the mount point '/' and the 'Use as' EXT4 file-system. Click OK
11) After that click the 'Install Now' button and follow the onscreen instructions.
12) You'll be prompted to restart after its finished, reboot and select the top option in the Grub 2 Boot Loader and you're now in Ubuntu.