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I'd like to try to help.
A box with a slash through it, *if* it is in the upper right hand corner, means 'a file has been tagged to be hidden'.
But I note that this symbol may not be in the upper right hand corner, and your camera appears to be disabled.
Things to try:
Check the memory card.
Try another memory card.
Try removing the batteries, and leaving the camera on a (dry, non-humid, non-dusty) shelf for overnight. Then put the batteries back in and try the camera again.
That symbol is not listed. It may be a 'general failure' error message, meaning that your camera is 'not up' or 'not capable of being initialized'. (This is not inconsistent with the memory card possibly not being right, being out of order, or needing another memory card.)