How can I reinstall Windows XP without logging into computer?

I haven’t logged into my HP for almost a year (I use my phone for Internet now) and I cannot remeber my password, there is no hint and it doesn’t recognize any of my fingerprints. When I bought the computer it did not come with an operating system disc. I do however have the product code located on the bottom of the computer. Is there a way I can reinstall my operating system without logging in? Please help 🙁