I want to make an old laptop as fast as possible and only use it for internet, but I'd also like to be able to boot to XP.

How do I delete what I installed, re partition, then install xubuntu?

ok...so i deleted a partition I shouldn't have, but it wasn't the c drive. This is on an old laptop that does not have anything critical on it but I'd like to get back to where I was before I started screwing around with it. Booting from the XP cd didn't work but booting from the ubuntu cd works fine. XP wouldn''t open in safe mode and i got the blue screen, and when I put the xp cd in it said "set up is configuring your hardware then the screen went blank. Would wiping everything then reinstalling xp work?

You should be able to repair your xp install by using your xp CD.  If that doesn't work, reinstall xp(though I would suggest upgrading if only because of security).  Then I would suggest you download parted magic live CD and resize the xp installation so you have enough room to install Ubuntu.

You can followthis to repair xp

If you want to wipe/reinstall both:

Use Gparted, etc to wipe/create 2 partitions.  Install XP first on one partition.  Then install xubuntu on the second partition.  When booting, pick which OS to boot into with Grub.