Newly installed Kubuntu boots to Windows instead
I just finished installing Kubuntu 12.04.1 on my laptop, which already had Windows 7 installed. The Windows boot partition is sda1; the Kubuntu boot partition is (or is supposed to be) sda6. The installation had a couple of minor burps that I didn't worry about. But now, when I reboot, I get into Windows rather than Kubuntu. I was expecting to see the Grub2 screen, offering me a choice of systems to boot to. I think I can get into Kubuntu by booting into SuperGrub, but I shouldn't have to. What might have gone wrong?