click start, settings, control panel, system,
advanced, startup and recovery.
if your using xp home with one harddrive and partition it may look like this. edit out the duplicated line to look like this.
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home
please note that this has to exact to enable windows to boot correctly
if your not sure to do this read up on this on http://hacks.oreilly.com/pub/h/591
also do not forget to copy this file
boot.ini and run your system backup first.