How do I uninstall ubuntu 8.04 from my desktop PC?

Hi Pete Walker,

Once you have overwritten your D partition, that will be used by Ubuntu. Since you have additional backup, you can just format the D-drive using Ubuntu live cd or by using Disk manager if you have windows installed in your PC. I suggest you to take a backup of important files if any.

--Murali

Pete, you may or may not have lost that partition data. It depends on what you chose when the partition manager gave you an option during the install. Do you recall the choice?
Next, Ubuntu doesn't name partitions and drives like windows, eg (Drive:D).
You should read up on this more but for now you probably have the following.
sda0, sda1 and maybe sda2. Since the old (drive:D) was a windows? compatible format
like fat, fat32, or ntfs, if Ubuntu left it alone it may show up under Places>Computer,
then look down left side for something showing a size MB or GB followed by Media.
This is a drive that is not mounted. Click on it.
Also when at >Computer, look at the right pane for /dev, expand it and scroll down for the sda....
If you chose to let Ubuntu use the whole disk, then its gone! It would have been formated
in the Linux file system ex3 for the system partition and a smaller memory Swap partition.
If your install created a duel boot with windows and Ubuntu, and you don't want to keep Ubuntu
then do as Murali says.
caveman