How to see graph directly after plot() via virtualbox?

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My laptop is windows7, so I use virtualbox as instructed on the Wiki. However, when I try the plot(), the sage always tell me that "launched png viewer for Graphics object consisting of XX primitives", and so far the only way I can see the image is to save the .png graph somewhere, which is inconvenient. I've seen on Mac that the graph directly popped out after plotting, so is there anyway to let virtualbox to do so?