With the impending demise of Windows XP, I have taken this opportunity to try Ubuntu (via a bootable USB stick) on a number of machines. Everything looked fine but the lack of a password concerned me so I created a password protected account and that's when the problems started. The system will no longer turn off (other than by brute force by holding down the power button for 6 seconds). When I select the shutdown option from the upper right of the desktop it simply brings me to a login screen. This screen also has a shutdown option in the upper right but selecting this has no effect (I suspect it just seemlessly brings me back to the same login screen, so there is no visible indication that it has had any effect). I'm using version 12.04 and bootable USB stick was created via Universal USB Installer from pendrivelinux.com (as suggested on ubuntu.com). If I also set a root password (via sudo passwd root) the problems are compounded in that it then becomes unbootable with the next boot failing with complaints about graphics cards and keyboard not being recognized. So, given my limited knowledge of Linux I have no idea if these problems are specific to the Ubuntu distribution or the way in which the UUI has packaged it up for a Live USB install, but if it is the former it would probably be worth looking into and if the latter then it might be worth not suggesting the use of UUI if it basically doesn't work. For now I shall move on to another distribution and see if it fares any better in creating a bootable USB stick. But if anyone has any suggestions for solutions to my apparent problems with Ubuntu I may try it again later.