I am now unable to install anything from the store, I think it happened after trying to install things from meecatalog and saying 'installation interrupted' I ran apt-get update and apt-get upgrade in the terminal and it was saying 'unable to lock /var/lib/dpkg is another process using it?'.

Now when I try running these commands it says 'the package unzip needs to be reinstalled, but I can't find an archive for it'

I am still able to install .deb files from filebox. Can anyone help me with this?

EDIT: When I try to install anything from the store it is saying it's an uncertified source, and then it says installation interrupted when I agree.