Cant you use the 'zoom' display mode? With this you can move the picture up to the top of the screen and then stretch it down to the bottom thus removing the black borders.
Goto Menu/Picture/Size... choose Zoom then you have two options highlighted - move up and down and stretch up and down.

If you already tried this then sorry to repeat but it should help the problem you have I think... but you might loose a little of the picture from either side.... which is ok for movies but not when playing games maybe.. anyway... good luck!
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I would suggest the zoom option too... u then have two controls - 1 to move the screen up or down and the other to change the screen size - try both buttons ;)
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Thanks for the above information, I have tried it and can only remove the border top and bottom. Looks like the I will have to put up with it. I am still concerned that I will get image retention over time.
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Do you mean image burn? If so you'll be pleased to know LCDs don't suffer from it :-)