Stuck on login screen, everything plugged in is unresponsive

Question

Whilst downloading version 14.04, my mother manually restarted the computer by holding the power button in. Upon restart, the mouse and keyboard do not work, the speakers would not play the start up sound, and a notification indicates there is no internet connection. Pressing the power button does prompt a window with options to restart, lock, or shut down does appear, so I assume the computer itself is functioning fine, but will not recognize anything plugged into it. The keyboard does work in the start up menus, but I don't know how to fix anything from there. Reformatting is not a huge issue if it comes to it, but I'd prefer to avoid that if possible.

Answer 1

Try magic key reboot:

Hold Alt+SYSRQ , and while holding, press one by one (with interval in 3 seconds or so ), R - E - I - S - U - B

If this doesn't work, try booting from live usb, go into try ubuntu , open terminal CtrlAltT, and do lsblk. Find which partition holds your ubuntu installation ( you should recognize it by size of the partition ), mount it with mount /dev/sda* /mnt , where * is the number of your partition. For instance, mine is /dev/sda5. Navigate to /mnt//etc/ and check the file sysctl.conf whether it has line kernel.sysrq=1, which enables the magic key (source: askubuntu).

Attempt live cd rescue for failed update/upgrade:

All while on live cd/usb:

1. sudo mount /dev/sda1 /mnt
2. sudo mount --bind /dev /mnt/dev
3. sudo mount --bind /proc /mnt/proc
4. sudo mount --bind /sys /mnt/sys
5. sudo chroot /mnt
6. apt-get update
7. apt-get upgrade

In addition I would run update-grub, but that's not required. If that doesn't help, repeat steps 1 - 6, and run sudo apt-get install --reinstall ubuntu-desktop gdm . You will be prompted to select gdm as default desktop manager, so do select gdm. Reboot. Source: help.ubuntu.com

Backup important data and reinstall the system

Make sure your keyboard and wireless card don't require proprietary drivers. After you have installed new system and rebooted, go into System Settings -> Software -> Additional Drivers, and make sure you have necessary drivers selected.