I have recently switched over to Win 7 64-bit but it seems this problem can affect Vista and XP users as well, in the last few days a large number of my dektop icons have turned black, I can get them back to normal (at least temporarily) by switching to high-colour (16 bit) [screenshot in link below]
http://vvcap.net/db/0ZsV3TSvF2LXSePscjcM.htp
however I hope a more satisfactory solution can be found, I did update the GeForce GT 230M driver but it has made no difference.
Thanks for any advice
Graham