I installed VirtualBox on my PC a few days ago just to tinker around with it and now the whole operating system has changed how it looks. The dock looks different, some of the icons are missing, the Software Center has disappeared. I don't know what happened. I use this OS mainly for Internet browsing and some light coding. The OS was working perfectly fine a few days ago but after installing VirtualBox and restarting, it has all changed. When I installed elementary OS, it was on version 0.3.2 and it still says the same now so I don't know why it looks completely different. I hope the image might help. Thanks!