I cannot post a comment so writing it in answer. Can you please elaborate a bit on what problem are you facing ? Here are the instructions that you should follow for dual boot installation :
Firstly, I would recommend you to create a backup of all the data.
If the computer does not boot from the CD (e.g. Windows starts again instead), reboot and check your BIOS settings by pressing F2, F12, Delete, or ESC. Select "boot from CD".
Proceed with installation until you are asked this question: "How do you want to partition the disk?".
If you have already partitioned the disk and left space for Ubuntu, install it to that and then follow the rest of the steps.
Otherwise, choose one of the next two steps.
Automatic partition resizing (recommended)
Choose the first option, which should say "Install them side by side, choosing between them each startup".
Specify the size of the new partition by dragging the slider at the bottom of the window.
Click on "Forward".
Continue on to Finishing Ubuntu Installation
Choose "Manually edit partition table".
Listed will be your current partitions.
Select the partition you want to resize and press Enter.
Select "Size:", press Enter.
Select Yes, press Enter.
Type in a new size in gigabytes for your partition, it's recommended you free up at least 10 GB of free space for your Ubuntu install. Press Enter when happy with your changes. It may take some time to apply the changes.
Create a swap partition of at least your amount of RAM (if you don't know, 2000 MB is a good value).
Create a partition for your Ubuntu installation.
Create other partitions if necessary.
Select "Finish partitioning and write changes to disk".
Reference : https://help.ubuntu.com/community/WindowsDualBoot
If you face any problem please update your question to describe the problem more precisely we will be happy to help you. Good Luck !