I am trying to install Ubuntu 12.04 from disk. I have partitioned my hdd so Ubuntu can be installed in it's own partition, i do not want to run it along side windows 7 which is already installed on my desktop.The problem i have is half way through the instillation, when i define which partition i want it to install on. The message i get is. ( No root system is defined, Correct from partition menu.) As i do not want it in the same partition as Win 7 that's as far as i get. i have tried a number of times, but cannot get past this message. I must be able to install Ubuntu in it's own partition but how!. My file system is NTFS.

when you set your partition scheme up, you should be allowed to choose which partition will be mounted under what label (i.e. /home, /boot etc). Have you configured a partition as / ?

You cant install linux to a NTFS partition. It will need to be a linux filesystem (EXT2/3/4, XFS, ReiserFS, etc..)

If I am correct, when you start installing Ubuntu it should have prompted you to "Install along with Windows".This will automatically take care of installing Ubuntu and configuring the partitons accordingly without disturbing windows.

But if you want to pick your custom partitions, then yes you need to mark a partition for / .

I would recommend to start your Windows and use the partition manager to delete the partition you made for Ubuntu. Then boot from the installation disk again and choose "use free space on disk" or similar when it comes to partitioning. It will take care automatically of making appropriate partitions with appropriate filesystems on it.