Linux Lite Kernel

[bfb]

Yes I have Lite 2.6 on it. That is what I am writing from. And every day when I log on I do an update.

I get

Code:

GPG error: http://extras.ubuntu.com trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 16126D3A3E5C1192
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package linux-headers-linuxlite-4.2.0
E: Couldn't find any package by regex 'linux-headers-linuxlite-4.2.0'

I have to explain that I installed Lite 2.6 from a Systamback Live USB that I made from the first computer,
since the one I want to install on doesn't recognise the USB I made with unetbootin with the 2.6 iso on it.
I also have as source Software from France