First of all, back up your data! Use Gparted to delete the partition you have Windows on. You could use it to delete the partition and add it to the one you have Ubuntu installed on. OS-Uninstaller is also another option. If you want to use Gparted, Evan Kroske has written an step-by-step walk-through:
Assuming you have installed Ubuntu on a separate partition, all you
have to do is remove your Windows partition and remove the Windows
option from your GRUB boot menu.
Make sure your backups of your documents (and other important files, such as ebooks, videos, music, and so forth) are current. If
you are going to expand the Ubuntu partition to take up the space
freed by removing your Windows partition, then this is especially
important, as there is always some risk (though small) of data loss
when performing dynamic partition resizing. However, even if you are
not planning to do this, unless you are highly experienced with
repartitioning, there is a significant risk that you may make a
mistake (you probably will not, but if you do, you want the
consequences to be minimally bad).
Boot from an Ubuntu live CD/DVD or live USB flash drive (as it is not considered safe to edit a physical disk's partition table from
within any of the operating systems installed on the physical disk).
Select Try Ubuntu
rather than Install Ubuntu
.
Use GParted, the GNOME Partition Editor, to edit the partition table on the hard disk, removing the Windows system.
- Start GParted (
System
> Administration
> GParted
, or if you're using a live system of Ubuntu 11.10 or later, press the
Super, i.e., Windows key, type gparted
, and
click the search result that appears).
- Select your Windows partition (it will be of type
NTFS
and will probably have a pale green border).
- Delete it (
Partition
> Delete
).
- Optionally, resize your Ubuntu partition to take up the freed space. You may be able to do this by selecting it (it's of type
ext4
) and using Partition
> Resize/Move
. However, if it is
contained in an extended partition (a kind of container partition for
other partitions) and the Windows partition was not contained in the
extended partition, then you may need to expand the extended partition
first, and then expand the Ubuntu ext4
partition contained within
it.
While this step is optional, the space that Windows
occupied will not be available to your Ubuntu system if you skip it.
(However, if you just want to use the space for storage, you could
create a new partition for that purpose where your Windows partition
used to be, instead of expanding Ubuntu's ext4
partition.)
- Apply your changes (
Edit
> Apply All Operations
).
Quit GParted and reboot (click the power icon at the upper-right corner of the screen and click Restart
or Shut Down
). Once you
have booted back into the Ubuntu system installed on the hard drive,
update your GRUB menu to remove the Windows option, by running sudo
update-grub
in a Terminal window
(Ctrl+Alt+T). When you run that
command, you might be prompted for your password. As you enter it, you
won't see any placeholder characters (like *
). That's OK--just type
it in and press enter. After you've run that command, Windows should
no longer appear as an option to select in the boot menu.
However, unless your Windows partition is seriously damaged or
infected with viruses, I wouldn't recommend removing it. Instead,
shrink your Windows partition, leaving space for your data plus an
extra gigabyte for virtual memory (the versions of GParted that come
with all currently supported Ubuntu releases are able to resize NTFS
partitions). You never know when you'll need to use an application
that only works with Windows.