A boot problem with Ubuntu?

did you install ubuntu on the same partition as windows 7?

was it on a separate HDD?

if its on a seperate HDD, make sure the ubuntu one is the first boot disk.

if its on one drive with different partitions, try holding down the "shift" key after powering on the machine. the grub menu should come up.

EDIT:

try installing the grub menu.

boot up from ubuntu live cd

Open the terminal from applications -> Accessories -> Terminal.

Then find the partition of your Ubuntu OS from the list generated with the command,

sudo fdisk -l

If your ubuntu(linux) partion is sda6,

sudo mkdir /media/sda6

sudo mount /dev/sda6 /media/sda6

After that you have to reinstall the GRUB

sudo grub-install --root-directory=/media/sda6 /dev/sda

If everything went alright you should be able to reach the GRUB boot menu when you restart the computer.

Reinstall Ubuntu using the Linux LiveCD.

Erase your hard drive and reinstall windows and ubuntu lol I don't know how to repair partitions in windows o ly on macs

This tutorial should help you restore the ubuntu bootloader.

Hope this helps

You can contact me by email if you need follow up.