My problem cannot be solved anymore because I reinstalled ubuntu 16.04. It works well.
I installed Ubuntu 16.04 in my old laptop Acer Aspire 3830 and installed the touchpad with the method I was not able to remember. After that day, I didn't use it. Today, I turned on my laptop. The keyboard and mouse were not working, but only the touchpad and some functional keys like on/off touchpad worked.
It is not a hardware problem, because I can use the keyboard in the other OS after multi-booting it.
I can edit grub at the boot menu, but cannot edit in Ubuntu desktop after entering the password using a screen keyboard.
Let me know possible solutions. Thanks.
