Managing and deleting partitions on the HD

So my laptop with Windows XP Home Edition was acting up and I had to install another OS to access and backup some files before using my Toshiba CD to revert the computer back to it's original configuration.

A quick search led me to Ubuntu (A Linux based OS) and I installed it. During the installation it created a partition on my HD. No biggie, I though, as the Toshiba CD was gonna get rid of it anyway.

Problem is, the CD didn't do everything I thought it would. See, it did indeed erase everything I had in the partition where Windows was and reinstall everything, but it didn't go anywhere near Ubuntu. So now when I turn my laptop on I'm greeted with a screen prompting me to choose between starting Ubuntu (Default first choice) or Windows.

Now, can anybody please tell me how to get everything the way it was, meaning how can I get rid of all the partitions in my computer, erase everything and then re-install the Toshiba CD from a clean slate to make it exactly the way it was when it left the factory? I assume simply formatting my HD from a DOS prompt won't do the trick.

Thanks.

Get or make a bootable floppy disk (if you don't have access to one, make one by downloading the 98SE OEM disk from http://www.bootdisk.com/bootdisk.htm ). Boot it, run FDisk, delete all partitions, then run the Toshiba restore disc.

Thanks, fellow Anonymous!