Icons unclickable randomly in W7

I have a desktop that is running W7 ULT 64bit (very well I might add) logged into a server 08 R2 domain. One issue that seems to happen completely randomly is the icons on the desktop become un-clickable. Logging off and back in sometimes fixes it, as does a complete reboot.

I don’t have any weird security policies that I could think of that would do something this drastic. Any ideas?