I have been using Ubuntu for the past two years along with windows. But I install it inside the windows using wubi. I will give your tip a try, hope everything will go well.
If you are using Windows Operating System and want to install Ubuntu or any other Linux distributions then follow the following easy steps:
1. Delete the last partition. For example, if you have three partitions C, D and E, then delete the partition E (make sure that it meets the space requirement).
2. Configure your bios to boot from CD/DVD.
3. Finally install any Linux distribution which will be installed on the deleted partition.