[kubuntu] Kubuntu 14.04 updates

I'm asking this on behalf of a friend who runs Kubuntu 14.04. For various reasons I haven't used Linux for some years and am getting a bit rusty but I think I know how to help her with some help from you.

She used to get notifications for new software updates but hasn't had any for some time. A couple of messages have been flashing up on the left side of the screen but they disappear too quickly for her to do a screen capture and she can't remember what they said. It happened while I was at the computer and one of them was from Apper but it was gone before I could read it.

So I tried a few things to find out what's going on. First I ran Muon Update Manager. It put up a message, "Last check for updates was over a week ago." but it gives no indication of when the last check was. Manually checking for updates gives the message, "E: Some index files failed to download. They have been ignored or old ones used instead." But it gives no indication as to which index files failed to download.

I then ran Muon Package Manager and ran a check for updates. It seemed to try to download the package lists then ended with the message, "Could not download packages". But it didn't say which ones and the Details button showed nothing.

So I ran Synaptic Package Manager and did a Reload. I got the same message, "E: Some files failed to download..." that I got with Muon Update Manager.

Lastly, I ran 'sudo apt-get update' in Konsole. I could see the lists it tried to retrieve and most of the items started with "Hit" but some started with "Ign" (ignore?). And again, I got the same "E: some files failed to download..." message. And again, there was no indication as to which ones failed. Unless that 'Ign' prefix was a clue?

I checked Muon Update Managers settings and "Show notifications for available updates" is checked.

So, my questions are:

1) How can I find out which sources lists failed to update?
2) How can I fix this?
3) How can I prevent it happening again?
4) How can I fix it so that she gets automatic notifications when updates are available?ufeff