I installed Dell factory Ubuntu Image into my Dell latitude 3550 model and every thing working fine.
But after that i used laptop for one of my project and for that i need to install some dependencies library and so many other thing for my SDK compilation. so after installing all that thing when i restart my laptop it's wifi and touchpad is not working. so for wifi when i enable some driver from additional drivers option provided by ubuntu (propriety driver) that wifi start working but i also enable touchpad driver but still my touchpad is not working. what should i do for making work my touchpad?