I'm having an odd problem on one of my Windows 7 machines. At machine startup, explorer.exe is working properly - I can use the Start menu, click on desktop icons, etc. At some later point, though, I lose the ability to interact with desktop icons. I can't double-click to open files on the desktop, and I can't right-click to see the properties window.

Oddly enough the Start menu still works properly, and I can still open an Explorer window into my desktop and access everything. I can get around the problem by killing explorer.exe and restarting it using Task Manager, but it's annoying to have to do this over and over.

Does anyone have any ideas? I took a look at startup files with msconfig and didn't see any obvious problems. Any suggestions would be appreciated.