I have just gotten my Ubuntu 12.04 LTS desktop computer reassembled after a trip back home and connected it to my parent's wireless Internet connection. The connection seems quite shaky (disconnects half the time, likely an ongoing issue with the wireless card I have installed), and it struggled to download updates because of the constant interruptions. Eventually, it managed to download the updated packages and started installing them. I got up and left it to do its work.

When I came back, I saw it was still having trouble staying connected to the wireless (no surprise there), but then I noticed that it seemed like Update Manager had stopped making progress on the installation. I opened the Details pane to see what it was last doing:

My guess was that the installation script for flashplugin-installer couldn't complete the download until I stabilized the Internet connection. I hooked my Ubuntu laptop up to my desktop via Ethernet and shared its wireless connection using this guide, and as I am typing this now from my desktop you can see that the connection issue was successfully worked around.

However, even with a stable connection established, Update Manager seems "stuck" at its current position and won't go any further. It's not totally frozen, but I can't do anything beyond open/close the Details pane as the Cancel button is grayed out.

I know it can cause big problems if updates are stopped during installation, but I'm at a loss as to how this situation should be handled. I'm sure it should finish normally if I can just find a way to restart Update Manager, but the question is how this should be approached. How can I safely get my updates to finish installing?