Over at http://www.bootdisk.com HOWEVER I'm sure you need the full XP Pro CD that was used to install your OS. The good news is that it's cheap (at least here.) Microsoft replaced mine for 35 bucks last month.
Suddenly my machine won't boot. It just keeps coming back to the same screen telling me windows had a problem and do I want to start windows normally or safe etc. None of the options work. Is there something I can download that I can use as a boot disc?