There are differences in the way Ubuntu and Kubuntu handle this in
the installer. Ubuntu's installer has the option to Install Ubuntu
alongside Windows 7 (see:
www.linuxbsdos.com/.../how-to-dual-boot-ubuntu-12-04-and-windows-7\
/
)
Kubuntu has only the Guided and Manual option. I've never done Guided.

Conversation here on how to dual boot Kubuntu:
askubuntu.com/.../how-do-i-partition-my-hard-drive-to-instal\
l-kubuntu
See also http://ubuntuguide.org/wiki/Kubuntu:Precise