I'm using a compal pbl-21, with the 64-bit version of Ubuntu 12.04. As far as I know, all of my drivers are current. However, when I open the disk drive and close it, Ubuntu becomes unresponsive, where the only thing I can do is manually power off the machine. I previously had the 32-bit of 12.04 installed (on the same computer), and this hadn't been an issue. Thanks in advance to anyone that can help.