Q I installed/upgraded from Ubuntu 7.10 to 8.04 and made a mistake with my screen display. It's now widescreen and is unreadable. I can go to recovery mode but that doesn't help, so I need a line in the root window to restore to, say, VESA 800x600 mode.
A There is indeed a one-line solution: go into a terminal and run
sudo dpkg-reconfigure xserver-xorg
This will run the configuration utility for the graphics system, where you can choose the correct settings this time. Not only does it help you when things break, it also means you can experiment with your settings secure in the knowledge that if you mess things up, rescue is at hand - an ideal situation for those of us who practice provocative maintenance.