Can’t Place Icons on Desktop in XP

In the course of trying to restore the Recycle Bin icon to my XP desktop (I had used TweakUI to hide it), I now cannot make ANY icon visible on the desktop. The checkmark by Recycle Bin in TweakUI can be checked (box not grayed out) but has no effect, and appears unchecked after a reboot. Also, creating a new shortcut on the desktop creates a .lnk in my Desktop folder in \Documents and Settings, but the icon for the shortcut is not visible on the actual desktop.

How can I restore icon visibility to my desktop?