Ok I had to replace my hard drive and I upgraded my RAM. I bought all parts through Dell and are the correct parts. The keyboard did work before but now all i get is a flash of light on the keyboard and than nothing. I am trying to reinstall XP but can't due to lack of keyboard. I have tried an extra keyboard and still nothing. The mouse works cd-roms,etc.. the keyboard is the only thing that doesn't. What can I do?