My DVD writer drive has disappeared from My Computer !. I am running XP Home and there is power to the drive - it opens/closes etc. There doesn't appear to be any reason for this. Prassi Primo picks up that the DVD writer is there but other software (e.g. games) do not detect it.
Have you gone to Device Manager to see if there is a problem with the DVD writer. You could try uninstalling it, restart your computer and let it detect the DVD all over again. Or, maybe the driver could be updated.