I'm new to Ubuntu. I tried reading all other relevant questions/answers, but couldn't find answer to my problem.
I have Dell Inspiron desktop, which came with Ubuntu older version 12.xx. Everything works fine and I upgraded to latest 14.04 last week. Everything installed fine, & everything works fine after first reboot (after upgrade).
But from next reboot onwards, keyboard and mouse are working. i can't login. KB/Mouse works fine in BIOS, I can go to Ubuntu boot menu.
I've tried twice now to reset to factory defaults, then upgrade to 14.04. Same problem continues in 14.04.
But beyond this, my knowledge in Ubuntu/linux is limited. Could anyone please help on how to fix this?
[I would really like to keep up to latest and NOT stay with older version]