Comuter does not show Desktop screen.

please repair your os it could be having boot error issues

either reinstall your xp operating system or change your booting up device .
to change that you must push the F key that it shows on the screen when you start up the computer i forget which key it is. that allows you to go in to a menu to change multiple things on your computer. but only mess with that if you know what you are doing because you might ruin your computer.
if your not to great with computers ill gladly explain the process on hot to change the boot device.