[xubuntu-users] Auto-update and notification appear to be dead

[MR ZenWiz]

I've had this happen before, but I can't remember what the (probably
easy) fix is.

I'm running Xubuntu 12.04 with the Precise kernel (3.8).  I have this
on both my work desktop and my home desktop.  On the work desktop, the
auto-update notification stopped about a week or two ago and I've been
doing manual updates with apt-get (update and dist-upgrade) since.

How do I reactivate the automatic update thing?

Thanks.

MR