I've been trying to set up a dual boot with Puppy and Kubuntu Linux but it's just not working. When I use GParted it shows multiple unallocated sections, a couple of swap files and so on. I think it's just better to wipe the whole thing clean and start over. What would be a good program to do that with? Thanks.

You can use fdisk to delete all of the partitions. If you opt for manually partitioning when installing Ubuntu, you should be able to do the same thing. Or you can start the install program of either, go to the psuedo console and use the fdisk program from there if you don't have a rescue disk handy.

How about Gparted? I mean the liveCD, btw, if you were referring to the Gparted that comes built into most distros today.

At the bottom of this page, there is a table of "Similar Threads" - the top two from this are almost identical to yours, and have the answers in them:

http://www.linuxquestions.org/questi...d.php?t=535043
http://www.linuxquestions.org/questi...d.php?t=449098

In essence, dd is probably your best bet.

Get the Slackware disc 1, boot with it, pressing <ENTER> for every prompt until you get to the main prompt. Then do 'fdisk /dev/hda'. Use 'p' to print to screen the current disk partition table. From there you can use 'd' to start deleting partitions until they're all gone. Then you can use 'n' to start making new ones. You'll want one for swap and at least two other primary partitions for your two OSes. For the swap, you'll have to use 't' to change the type; select that partition number (1 if you do the swap first) and use type 82. Then you could make the last one a logical so you could break it up into pieces later if you want.
Then do 'p' again to see the final result. If you like it, use 'w' to write this new table. Your hard drive is now blank and ready for installations. Unless you have some special circumstances, "wiping" the drive probably isn't necessary beyond what I have just described.