Just an idea.....boot from the CD to completion, bring up console, type "sudo su" [without quotes] and run cfdisk. Look at your primary LINUX partition and make sure it is set to bootable. That is the first choice in the several choices at bottom of screen. You could use qtparted, but i am not too familiar with that program. But cfdisk is pretty simple to use. Just look for your PRIMARY LINUX PARTITION......on that same line you should see the word 'boot'. If not, look at bottom of screen. bootable is the first choice. Just hit "enter" then press right arrow key to "write", press enter....then press right arrow key all the way round till you come to QUIT or EXIT. Reboot and cross your fingers! Hope this helps.