Here's a screenshot that might help. Basically, I'm trying to partition this hard drive which currently only has Ubuntu 13.04. However, GParted does not allow me to do anything. When I click on "Unmount", it shows this error. And so, I basically can't do anything to make a partition. Any ideas on how to fix this?
if you want to install windows you should not run the cd or dvd inside ubuntu..First use a live ubuntu usb or dvd, re-size or format the ext4 partition using gparted and create a new ntfs partition with the space you got, then restart the system with windows dvd and install it in the newly created ntfs partition..
NOTE: The new partition should not be a extended partition..once you install windows grub will not show up and you also won't be able to find ubuntu option in windows boot page so i highly recommend you to install windows first then install ubuntu in a separate partition...