You are not alone. I, too, tidy my desk by putting things back in the IN basket. At least then I know where it is.
The problem with an IN basket is that the old stuff get buried. I sometimes flip the contents over so that I am processing the older things first.
Esquire is right, baby steps.
Have you tried just working on your IN basket in 10-15 minute spurts. I sometimes find, as I am shutting up the house for the night, putting the cats out etc, I sit at my desk and just do a little bit of sorting. Everthing is quiet and I am more productive. Works for me, hope it helps you.