hi,
heres what you need to do:
1.restart the pc, when the pc shows the device listing screen(the screen that's shown before the XP logo when the pc is booting), press the 'delete' key on your keyboard. this will take you into the pc's setup utility.
2. look for a 'BIOS features' menu, select it and press the 'Enter' key on your keyboard. this will take you to a menu 'first boot device' (from which you can choose to start up from a cd-rom)
3. make sure that 'Floppy' is not selected as the first boot device, once you are sure that you have made the above mentioned changes, navigate back to the setup utility screen that you saw when you followed
step1
4. insert the XP cd and select the option to save the changes you made as required by the utility menu.
once you've saved the changes, your pc should automatically restart from the XP cd, then just follw the instructions as required by the XP setup program..as the XP setup takes you through the steps required to install XP you should look for the option to full format the drive(eg C: or F

on which XP will be installed..then just follow the promts as normal.
when you're done with the installation, you should reset the floppy as your first boot device(ie undo what you did in step2).
that's it! you should be ready to use your pc as normal, provided you re-install all the other software you were using before the XP Re-install.
good luck with keeping those teen hormones in check...
cheers buddy!