If Explorer is shown a directory with some corrupt AVI or JPEG than it will lock up and you see your issue. Microsoft has not provided a fix for this one yet.
The other repeatable was related to what I noted and Nero Scout. To fix that I had to uninstall Nero Scout since Nero would have to re-do their code to not rely on MSFT for a fix.
These are two with causes and no fix. More about malware causes at http://forums.cnet.com/5208-6122_102-0.html?threadID=328220#2968150
Every now and then the icons in the system tray freeze, and when I put my mouse over the windows the text disappears and the tool tips are blank black squares... how can I fix this? >.>
(a temporary for me to fix this problem is to kill the explorer.exe process and restart it)