Based on the information you gave:

• /dev/sda1 is a Windows 7 bootloader


• /dev/sda2 is probably an OEM recovery partition


• /dev/sda3 is The 400GB Windows 7 paritition


• /dev/sda4 is the 200GB extra partition where you can install Ubuntu

Under Windows this is probably accessed as D: drive. Only proceed if you have not used it and there is nothing in the drive, else backup whatever data you have put there.

You can then proceed as Robert has said in his answer.

If you want to have a swap partition however, things are a little more complicated because the manufacturer (OEM) has already used up all four primary partitions that it is possible to have. The way around this is to delete /dev/sda4 completely and create an extended partition in its place. You can then have two logical partitions within this extended partition - One for Ubuntu / (root) and one for the swap file.

Two reasons why a swap partition is desirable:

1. Swap partitions are used for hibernation. If the computer is a laptop and you want to be able to hibernate rather than suspend, you'll need a swap partition. Hibernation saves the current state of the computer on the swap partition and then powers down completely. Suspending only powers down peripherals but maintains the computer state in RAM, therefore it still uses some power. It's possible to suspend your computer and leave it longer than expected, only to find that the battery has gone flat. Hibernation is suitable for when you want to leave the computer for longer periods, or if you are not sure how long you will be away from it.


2. Swap partitions can be used as RAM if things get tight. If you only have a small amount of RAM (usually 1GB or less) then a swap partition can be helpful, to keep a bit more RAM available for system use.

I have the following suggestion which will get you installed in the easiest manner, with a swap file.

1. Boot off the LiveCD or LiveUSB and Select "Try Ubuntu"


2. When booted, run Gparted and delete the /dev/sda4 partition. Make sure you click the button to commit the change to disk otherwise it will not actually delete the partition.


3. Click "install" to start the installation


4. When asked, select "install alongside Windows"

Since there will be blank unformatted space Ubiquity (the installer) will make an extended partition on which it will then make the / partition and a swap partition and install Ubuntu accordingly. If you want to do a more manual operation you can create the Extended partition, and then create the logical main partition and swap partition inside it if you wish, but the end result will really be the same.