If you are up to doing some work in a terminal, it looks like grub didn't install properly. Boot from whatever media you used to do the installation, and once at the desktop open a terminal, then once at the prompt type the following command, and press enter after each one:
Next re-install grub:
sudo mount /dev/sda7 /mnt
sudo mount -o bind /dev /mnt/dev
sudo mount -o bind /sys /mnt/sys
sudo mount -o bind /proc /mnt/proc
sudo chroot /mnt
sudo grub-isntall /dev/sda
you should see a listing of your installed operating systems, plus memtest. Press Ctrl-d twice, then reboot.
This should solve your problem.