The laptop isn't ruined, software problems can always be fixed or at least overcome. The only thing that concerns me is that you may end up having to wipe the disk and start again, which means all your personal data will be gone.
I think HP laptops come with a recovery CD rather than an XP installation CD which means I'm not 100% on how they work. If you dig it out, put it in the CD drive and boot the laptop, it should bring up a menu from the CD. There may be an option to repair the installation or to reinstall the operating system over the one that's already there. Either of these options will prevent your personal files from being wiped, but I'm not sure that it will fix your problem (I'm 96% sure it will!).
If it works, excellent, but if it doesn't, then you're going to have to think about formatting the disk and doing a fresh install from your CD. Doing this will reset the laptop to factory conditions and will get rid of anything you've put on there. If you're happy to do this, or if you're fully backed up, or there's nothing on there to lose, then this is by far the best option. Exactly how this works, I'm not sure, but there should be an option when you boot the PC from the CD.
I have a friend who has done the same thing to his HP laptop, I'll ask him if there's anything he can remember about how this all works and post back if there's anything else useful I can find out. Good luck!