Usually, such a behaviour is caused by a bad shell extension.
The programs from http://www.nirsoft.net/utils/shell_menu_view.html and http://www.nirsoft.net/utils/shexview.html (both free) should help you find it.
Whenever I right-click on a file name in Explorer the screen dims and clocks, and the file parameters don't display. I have to shut down explorer. I can open files, just not right click. This seems to be a new problem!!