If the computer will not boot and the dvd drive is bad. You will have to find an alternate way to boot the computer.
I used a thumbdrive since the bios supported it.
In order to get access to the windows drives you should do a
fdisk -l to see the physical devices.
You will have to mount whichever drive you need to get the data from.
mount /dev/hda1 /mnt/windows1 -t ntfs -r
Once you have the drive you need you can get your backup device setup.
I used a usb hard drive(beware some only turn on when active –MyBook)
Now you can do a copy
cp -r /mnt/windows1 /mnt/usbharddrive
Voila you have your valuable data again.