Can I reinstall Windows Xp without the cd

I have a Dell laptop that came with no OS. I added XP but now it says it has expired and I have to purchase a new one. I don't know bout neone else, but I don't have 200 dollars to go but another one and I lost the disc that I had. So can I reinstall the thing off my harddrive?

If you have a COA - Certificate of Authenticity - license, I think you can use another person's cd as long as you have that. If you don't have a valid COA, that is piracy. Have you tried one of the version of Linux? There are some cool distros that rock.

No i don't have the authentication, I was just wondering if I could restore it from the hard drive.