Screen became smaller, kind of zoom - (minus)

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I am using linux mint 12 KDE on hp dv6. Today I downloaded a file (a game bot) and after opening that file, my window screen became somewhat smaller e.g. fonts, icons etc smaller. First I tried to bring fonts back to normal which I did by increasing their sizes but no desireble result... After some time, I realized that the taskbar icons are also smaller. So, it has to do something with system file.

If any expert on the matter is lurking here, please offer the suggestions on how to bring back my normal desktop. thanx in advance.