I tried updating using update manager and I got error saying requires installation of untrusted package.
I tried typing get update and get upgrade command in terminal but no avail.
but following shows the result after "get update" in terminal.
W: GPG error: http:// archive.canonical.com precise Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: GPG error: http:// archive.ubuntu.com precise Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: GPG error: http:// dell.archive.canonical.com precise-dell Release: The following signatures were invalid: BADSIG F9FDA6BED73CDC22 Canonical Archive Automatic Signing Key <ftpmaster@canonical.com>
Here is screen shot for your reference
I am a very new user to ubuntu. Please help and explain as if you are explaining a child.
