Dual boot ubuntu 13.10 and windows 7

[Kartikey Kant]

I want to install Ubuntu 13.10 on my pre-installed windows 7 pc and I want a dual boot. I have no empty partition on my hard disk drive. I don't want to re-install windows 7. How should I do it? Please answer in steps. Also suggest the amount of space I should allocte to ubuntu 13.10.

[OrangeCrate]

A good set of instructions on dual booting is here:

http://ubuntuguide.org/wiki/Ubuntu_Saucy_Installation#Dual-Booting_Windows_and_Ubuntu

[oldfred]

Some more info:

My laptop already has 4 primary partitions: how can I install Ubuntu?
http://askubuntu.com/questions/149821/my-laptop-already-has-4-primary-partitions-how-can-i-install-ubuntu
Good advice on how to handle all four primary partitions used. - srs5694
http://ubuntuforums.org/showthread.php?t=1686440
Be sure to create recovery DVD(s) first. And a Windows repair CD.
HP tools partition discussion - similar for other vendor partitions:
http://h30434.www3.hp.com/t5/Notebook-Hardware/Hp-Tools-Partion/td-p/228360
For a complete blow-by-blow on dealing with HP's four partitions, see Full Circle Magazine, issue 41, page 36. - gordintoronto
http://fullcirclemagazine.org/
This suggests removing system partition and making c: the bootable partition. But has details on all alternatives
http://h30434.www3.hp.com/t5/Other-Notebook-PC-Questions/How-to-repartition-HDD-of-HP-notebook-with-pre-installed/td-p/742019
Shrinking a Windows 7 partition is best done in Windows. But do not create new partitions with Windows.
http://www.howtogeek.com/howto/windows-vista/resize-a-partition-for-free-in-windows-vista/
The Hedge show graphically how to delete & create partitions:
http://ubuntuforums.org/showthread.php?t=1713649