touchpad not working on Ubuntu 14.04

Is there a switch or shortcut to enable / disable the pad?

thanks for the quick response - much appreciated.

there is no switch to enable/disable the pad. When i run the diagnostics at boot time (F12) the touchpad works. AS soon as ai get into Ubuntu - it's either not there or is frozen. External mouse works.

is there any way I can clean up the installation totally & do a fresh install of Ubuntu? I don't have a windows setup to work from.

There may be a fix:

run:
sudo gedit /etc/default/grub

Change:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

To:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i8042.reset"

Save the new file and close gedit. Then run:
sudo update-grub

Reboot to test

tried that - no luck.

I think the system is corrupted. It's probably best to do a format & reinstall & then retry. I have reinstalled previously but did not understand the different options that were given since I am, historically, a windows user. Pls can you give me some clear instructions to wipe out what I have & reinstall from scratch.

Also - I have another laptop installed with the 32bit version of 14.04 - when I add some update, it does not work. Do you suggest I go to an earlier version which is less problematic?

Instead of:
i8042.reset

try:
i8042.nomux

Precise (Ubuntu 12.04) is supported til April 2017 and you can then install 16.04 LTS when it comes out in April of the same year

between your previous response & this, I had erased the disk & reinstalled 14.04 & updates. I noticed the ff:

1) After reboot, there was a command line error tha popped up & disappeared - something to the effect of " link training error 3". The system then goes into a GRUB boot menu with Ubuntu as a choice.

2) When I ran the sudo gedit, i got the ff. error :
(gedit:5410): Gtk-WARNING **: Calling Inhibit failed: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files

3) running the sudo update-grub, gives the ff:
(gedit:5410): Gtk-WARNING **: Calling Inhibit failed: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files

I feel there is something still lurking in the background even though I erased the disk before installation.

I've tried whatever you'll have suggested - but nothing works. Pls tell me how I can uninstall Ubuntu completely & reinstall Windows (with the idea being to then install dual boot). When I boot off a windows7 usb, I get the error : "BIOS not fully ACPI compliant"

Boot to the Windows CD and delete all partitions (obviously backup what you need first) but leave unpartitioned space with which to install Ubuntu. Install Windows as usual then boot to the Ubuntu CD and install to the freed space.

I tried the solution at : http://askubuntu.com/questions/592925/dell-inspiron-3551-unresponsive-touchpad

that resolved the touchpad problem. It's working now. Thanks for all your effort :)

I will raise another issue re. my last comment.