I have a Compaq presario 5000 that I boutht about 4 years ago, I recently turn it on and the monitor doesn't show anything, I thought I might be the video card, replace it and still doesn't work, the computer has power but the cd rom doesn't open, do you know what it might be?

First, make sure everything is plugged in correctly inside the computer. Then, make sure the CPU is in the socket correctly. If it still does not work it could be a Power Supply or Motherboard problem.