Ubuntu – Network manager gone after update

This happened to me in the past but I never got around to troubleshooting it. Generally, with this kind of intermittent problem I'll use the following script to both keep the application running and gather information about why it quit:

#!/bin/bash
# Automatically relaunch applications that exit unexpectedly, and log stdout for analysis.
# Usage: relauncher.sh "application"

# Command to (re)run
app="$1"

# Infinite loop
while true; do

    # Get starting time
    start_epoch=$(date +%s)

    # Run application and capture output in memory
    log=$( { $app ; } 2>&1 )

    # Run in background
    {
        # Notify in system tray (Waits here until clicked)
        zenity --notification --text "$app has exited. Click to view details."

        # Write log to temp file
        logfile="$(mktemp)"
        echo "$log" > "$logfile"

        # View it
        gedit "$logfile"
    } &

    # Abort if the application exited too quickly
    end_epoch=$(date +%s)
    duration=$(( $end_epoch - $start_epoch ))
    if [[ "$duration" < 30 ]]; then
        zenity --notification --text "$app exited too quickly. Aborting relauncher." &
        exit
    fi

done

exit

To use it, save an executable copy as ~/bin/relauncher.sh and then, in System ▸ Preferences ▸ Startup Applications ▸ Startup Programs ▸ Network Manager ▸ Edit, replace nm-applet --sm-disable with /home/user/bin/relauncher.sh "nm-applet --sm-disable".

The next time the applet disappears, it will be automatically restarted and an icon will appear in the notification area. Click the icon to check for information about why nm-applet exited, then consider reporting a bug via ubuntu-bug nm-applet and attach any relevant error messages.

I eventually fixed this by using a PCI network card. I was still getting the message in Network Manager that the device wasn't managed, so I followed the instructions in this question. I am finally back to normal! Thanks for everyone's help.

P.S. Also fixed the display resolution being stuck at 640×480 by following this article (#1 solution worked for me)