I just did a fresh install of Elementary OS on a Dell 13-7352. During installation the trackpad was working, but afterwards it stopped. I have tried this:
sudo apt-get --purge autoremove xserver-xorg-input-synaptics && sudo apt-get install xserver-xorg-input-synaptics
which worked previously on Ubuntu 14.04 on the same computer but had no luck. I have also tried a few other fixes but nothing seems to be working. Any other ideas?