I recently had to rebuild a Dell Latitude D610 as it was not working properly on purchase. The reinstall instructions for Windows XP SP2 included installing the relevant Dell drivers from the Dell CD (or internet download if they were later versions). The Notebook System Software (NSS) always failed to install - it would crash upon starting the program.
After phoning Dell Technical Support to fix this problem, the answer was to run the software whilst in Windows XP Safe Mode. To get to this reboot your computer and press F8 just before the Windows logo appears (easiest thing to do is press F8 repeatedly as soon as the computer boots and you are sure to get the option for Safe Mode).
After installing it in Safe Mode you can reboot into normal Windows XP.