Step 1. Install Windows 7 or XP as u like
Step 2. Put Ubuntu CD in your CD tray
Step 3. Open My Computer , you will see like this
Step 4. Double click on the drive ,where the CD is , here I drive
Step 5. Now you will see a window like this
Step 6. Chose the second option “Install Inside windows” and click on it, now you will get a window like this
Step 7. First chose the drive where you want to install it, you can also chose c drive
Step 8. Now chose the installation size , i recommend 6 GB.
Step 9. Give a username and password and click install
Step 10. A new window will open showing installation process , after complete of installation , remove your CD and restart .
Step 11. Now in boot screen you will see Ubuntu and Windows , chose Ubuntu .now you will see a another boot screen by Ubuntu , chose first option . Now the Ubuntu will on, and necessary file will automatically install .thats all. Ubuntu is is install now in your PC
N.B. If you want to remove Ubuntu , just go to control panel in Windows and uninstall Ubuntu.You can also apply this same method to duel boot Ubuntu With Windows 8