Ubuntu 16.04 is installed on my laptop.
Yesterday I installed Windows 7 in unallocated space. When I restart my laptop, I don't get any menu to choose what OS to boot into. It just automatically boots into Windows.
I thought I might have accidentally removed Ubuntu and so I wrote Ubuntu on a USB and tried reinstalling. That installer says I already have Ubuntu and is making me choose whether or not I want to erase and reinstall, so it isn't removed.
How can I boot into it?