If everything was working before you installed the DVD drive, you probably by accident loosened a cable. I would one by one check that all cables are where they need to be using the manual for the motherboard, and reseat every one of them. If everything connection wise seems good, unhook all of the power and sata cables from the DVD drive. Sounds like you have a loose power connection somewhere or accidentally static dis-charged damaging the motherboard but I doubt it since you had to touch the case when you were installing the new drive.