I got a new laptop with ubuntu ready to be installed from the factory. I installed to near the end that it's ask me to key-in login, password, retyped password and computer name. Then, I came to my old laptop to do something else. When I went back, it showed me the normal login page.
But I try to login but it's falied. I know exactly what my password is but the problem is it may be too long and it may be accidentally the same with the retyped.
I thought that it's now a problem since I just re-install it from the boot menu using one from factory.
But the problem is that there is no more boot menu. So how can I bring back the boot menu?
I have tried everything in this question:
Either left shift, right shift or both didn't help. That's why my question is 'bring back' rather than 'display'.