Thanks for the additional information.
The large number of package to update indicates that your /etc/apt/sources.list got modified to a different version of ubuntu than the one you installed (or upgraded) too. Could you please attach that file too?
Thanks for the additional information.
The large number of package to update indicates that your /etc/apt/ sources. list got modified to a different version of ubuntu than the one you installed (or upgraded) too. Could you please attach that file too?