First, the CD with Windows 7 is not a CD. Windows 7 does not fit on a CD, and neither does Ubuntu anymore. You need a DVD. Second, I wouldn't think that CD you got with Windows on it is writable, you may need to make another DVD. Just burn the Ubuntu image to the DVD and you should be set. If you don't have a DVD, you can do a crude hack that I came up with to install from USB really easily. I'll put it here, but you will need some terminal knowledge.
- Mount the EFI hidden partition.
mkdir mnt ; sudo mount -t msdos /dev/disk0s1 mnt
- Extract the Ubuntu iso. You can use "The Unarchiver" from the Mac App Store.
- Grab the file called
grubx64.efi or similar. It may also be named
bootx64.efi. Put this in
mnt/EFI/BOOT and name it
- You need to copy the iso image to a flash drive. This will delete all data on the flash drive.
dd if=ubuntu.iso of=/dev/disk<usbdisk> bs=4m. You can find what disk is the flash drive by using
- When this finishes, take your drive out and put it back in. It may take a while. Using the rdisk variant of the device node may make it faster.
- Restart the computer holding the option key. Select
- The EFI GRUB menu will load up if you did all this correctly, and you can boot Ubuntu.
Again, this is only needed if you want to do an installation from USB on your mac. Even then I am sure there is another way, such as rEFIt.