several things here. It looks to me like the machine has some issues with the hardware in the system. Start by uninstall the CD/DVD drives and physically disconnect them from the system. Then runinstall the IDE channels that are being used for the CD/DVD drives. then reboot. let the system come up and install what it wants, then shutdown and add the CD/DVD drives back to the system. see if that helps.
If not, i would suggest checking system restore for any restorations point greater then 3 months back. This may pose a problem for you, but aside from that a rebuild might be the only solution left...