As already offered above, you should be able to use another XP CD to install Windows again. However, the key on the lappy sticker will (usually) only be accepted by another OEM disk (HP, Sony another Dell) and not a retail version of the OS.
If your key is not accepted, there are ways to create an OEM disk from a retail version. All OEM and retail XP disks are bootable.
As far as I recall, Dell stopped using recovery partitions around 03 or 04 for units shipped to the states and shipped PCs with an OEM XP disk.
Good Luck!
You may want to download the drivers for network, sound and video bits from Dell.com/support before installation.