[ubuntu] 12.04 - cannot search applications in Unity Dash any more?

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http://ubuntuforums.org – This was working OK previously but now no applications appear when running a search in the Dash or even show when first opened, it just shows recent files and downloads. If I type 'terminal' for example, it says "sorry, there is nothing that matches that search". I had installed some printer drives and stuff for KDE/plasma yesterday, could that be the problem? (Hardware)