My home computer used to freeze whenever I right-clicked the desktop, and the only fix was to kill the explorer instance and start it again. Major PITA. First I figured I had a virus or something, but when a scan came up clean, I figured there had to be something wrong with the registry.
A quick google search turned up this excellent article:
Problems when you right-click an empty area in the Desktop?
If you have a problem when you right-click on a blank area on the Desktop, then you need to inspect the handlers in this registry key. ...
HKEY_CLASSES_ROOT \ Directory \ Background \ shellex \ ContextMenuHandlersThe only handler present by default (in a clean XP installation) is the New handler. If you find any additional sub-keys there, it may have be added by third-party applications.
And should you ever get too trigger-happy and delete too much, this Knowlege Base Article will come to your rescue: