This guy seems to indicate that he had [link|http://gvriese.blogspot.com/2006/06/computer-woes.html|Ubuntu running on it].
With a little digging, it should be possible to determine the motherboard and all the details - maybe by downloading the manual for the system from HP. I can't imagine that it uses anything that Kubuntu would have trouble with, but I can't guarantee it of course.
HTH. Good luck!
Cheers,
Scott.