[ubuntu] Aspect ratio problem in VirtualBox after Ubuntu Update

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http://ubuntuforums.org – Only just installed VirtualBox with Ubuntu as a guest OS on my Win7 64-bit PC a couple of days ago, so a real beginner, and already having problems. Started Ubuntu in VirtualBox today, and was told I had Ubuntu updates waiting, just like Windows Update. I said go ahead, and they were installed (53Mb). I had to reboot the Ubuntu guest OS afterwards. That's when my problems started. I discovered I needed to reboot the host OS, and re-install Guest Additions in VirtualBox, after which some of the problems went away, but I'm left with this annoying one: Before the update, Ubuntu fitted nicely (Hardware)