I'm having a very similar problem, and I'm using Windows Vista Business (final release, purchased etc.) The start menu works fine for quite a while, but every once in a while it stops working correctly, and exhibits similar problems to the ones you're having.
I'm using the classic start menu, and when the problem occurs clicking on any item in the start menu simply closes the start menu. This includes menus. Rolling over the menus still works, but even the sub-menus don't work and clicking them just closes the entire start menu.
The problem also seems to affect grouped programs in the taskbar. For example, if I have 10 explorer windows open and they're grouped, when I click on the group it'll show me the list of the windows, but when I click on any of the items in that menu, the menu closes and nothing happens.
The way to fix the issue for now is to kill the explorer process using the task manager, and running explorer again (again, from the task manager). Rebooting also works, obviously. I hope there's a more permanent solution to the problem though, because it's pretty annoying.
Any help is appreciated!
Is anyone else having a problem with clicking links in the start menu of recently opened programs and getting no response.
I can open up some programs in the recently opened program list with no problems, but some programs will not work UNTIL I go into the "ALL PROGRAMS" folders and click their link there.
Even after clearing out the recently opened programs list and opening some programs in the Start menu of the all programs list (which open the programs fine, the program or programs show up (as they should) in the recently opened program list...
But again clicking on those shortcut links in the recently opened programs list will NOT open up the program. This happens to many, but not all, programs.
It appears I may just need to "turn off" the recently opened program option and just "dig" into the all programs menu listing to open up the program I need from there.
Anyone have any ideas how to solve my issue?

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