I have a Windows 7 64 bit system which has a strange problem for past several months: After the computer runs for several days continuously a problem is encountered where clicking on the task bar to launch applications fail to launch the GUI of those applications. The failed applications could be as simple as the Notepad or the Calculator. So when I click on the application icon in task bar they get highlighted but don't launch. They do launch if I close some other running GUIs (such as Outlook). And as far as I can remember the Task Manager does show the 'process' of the failed-launch application.
I don't know much about Windows GUI/windows management but my guess is something to do with 'stacks' of windows: Not enough space to show new windows unless some existing ones are closed? The problem goes away for several days once I restart the computer.
Any idea? Thanks!