Cleaning Windows From Ubuntu

When Im installing ubuntu, I only doing "next - next" way, I forgot the detail, I just choosing that I think is the safest option. And the result is I succeed installing, I already had my ubuntu, but one that for me is minus thing that there are windows still in my notebook. When I starting open my notebook there still option for XP or even Vista booting. In fact I already donot want to use windows anymore, so I want to clean them from my notebook

I joined the id-ubuntu forum as suggested by yanu, I post them about my problems, I want to remove the windows things without re-installing again, because Im affraid if I fail to install it all over again. And one of the reply is I try to.
- install Gparted, is just as partition magic
just System->Administration->Synaptic Package Manager, and search : "gparted", and then click apply, or I think we can doing the same thing from Application ->Add/Remove, and search: "gparted", and click it and install it.
- If the install is done, it placed in System-> Administration -> Partition Editor, gparted is for Gnome Parted :d
- so I run the program, it just as the partition magic, the above boxes shows the partition of our storage, firstly I donot know which boxes I must change, thanks for yanu for helping me again.
- My harddisk (also when using windows), is only have two partitions, drive C and D, In Ubuntu, it read as /media/disk (C), and /media/data (D), I think because when in windows, the name of the directory is C:disk and D:Data. I forgot the exact.
- So my job is choosing the /media/disk and right click and change the file system from NTFS into Fat32 or the linux type, sorry I forgot the name, and gparted is cannot open right now
- And then in the /boot/grub/menu.lst,I commented the lines that execute windows booting, here is the complete code:
# This entry automatically added by the Debian installer for a non-linux OS
# on /dev/sda2
#title Microsoft Windows XP Professional
#root (hd0,1)
#savedefault
#makeactive
#chainloader +1
- restart it and there will be no more windows booting option. and the /media/disk is now clean and I get more spaces