[sparticus]

I am putting a computer together for my daughter. Its an older machine that worked a year or so ago when it was last used. My problem is after putting in the HD (a used one with win XP on it) the computer wont POST when I try and start it. I put a new power supply in as part of the work to get it ready, but just in case I also tried a known good power supply, it still has the same problem. In my troubleshooting I have swaped out video cards and RAM all to no avail. Any one have any ideas? I'm not sure if its necessary but do I need to reformat the HD before I can put it in the different box?

Thanks for any help you can provide.