Tried an experiment, I took a flash picture of a flower head using 800 ISO. Edited it with Elements 3 and slightly over sharpened it.

Then in PSP 7 I went into Effects - noise and used 'Edge preserving smooth' set at the highest resolution.

Next I went back to the original and without over sharpening it I also used Edge preserving smooth.

The result shows well in the lower pic.

This was taken from the centre of the composite.

Top left over sharpened. Top right oversharpened smoothed.

Bottom left original,

bottom right original smoothed.

It shows better viewed large there is a slight overlapping in the pasting of the copy images.