How do I remove Ubuntu, wipe hard drive and install Windows XP?

I have ubuntu 11.10, but i want to remove it, format my hard drive and install windows xp, but when i try doing this from the windows installer it says that the hard drive can't be formated so i would like to do it from the ubuntu installer without installing it again. Please help me thanks.

The easiest way to do this is to probably create a new partition table on the drive from the Ubuntu live CD/DVD or USB flash drive. This is lower-level than just removing all the partitions.

1. Boot from the Ubuntu live CD/DVD or USB flash drive.
2. Select Try Ubuntu (not Install Ubuntu).
3. Run the GParted Partition Editor.
   • To do this, you can click the Ubuntu button at the upper-left corner, type in gparted, then click on the GParted icon when it comes up.
4. Make sure the proper drive is selected in the drop-down menu at the upper-right corner of the GParted window.
   • If you have other drives and the wrong one is selected, you can lose data on them! You do not want to create a new partition table on the wrong drive.
5. Click Device > Create Partition Table....
   • Make sure any important files on the drive have been put somewhere else, before doing this!
6. Click OK in the window that comes up. (You can, and should, almost always stick with the default "MS-DOS" style of partition table.)
7. Quit GParted and reboot the system.
8. Install Windows on the newly "blank" disk.

The GParted window will look something like this, though not exactly like it.

Warning: this will completely wipe your hard drive, so if you have any documents/data on the installed Ubuntu back them up to a USB first!

Assuming you have only one hard drive, and you want to remove Ubuntu 11.10 and format the drive, please do this:

1. Boot from the Ubuntu Installer/Live CD, and choose "Try Ubuntu..."
2. At the Live Desktop, press Ctrl-Alt-T to open a terminal.
3. In the terminal, type: sudo dd if=/dev/zero of=/dev/sda bs=1M count=8 && sync
4. Shut-down the LiveCD.
5. Insert the Windows XP CD and start it; the XP installer should now detect the blank hard drive.

Note: *If your computer is very old and uses IDE cables for the hard drives (wide connector), you may have to use hda instead of sda