If the key information you seek is the key supplied from Microsoft to be used at
the time of installing the XP operating system, then
if you run BelArc Advisor (free Internet download) the key will be shown on the
printout. BelArc lists all the hardware and software installed in the computer
along with much details. You have to install BelArc on the machine in question,
so you have to be able to boot the OS, install BelArc, so BelArc can analyze and
display the results.