Trobleshooting Windows 7 desktop shortcuts

[robilong]

Is there any known reason and fix, when Windows 7 Enterprise desktop shortcut key stops to work?
Win+D doesn't, while Win+E works.
When hiding other applications and revealing desktop, application shortcut keys don't work from desktop but start from task bar icons.

I have experienced this problem rather many times and problem is gone after restart.
But I'd like to decide myself when to restart Windows

Thanks!

 

[robilong]

I spent some time troubleshooting and found that reason is in MSIE 9.0. When MSIE is closed on desktop it doesn't end processes in task manager. When iexplore.exe is closed from task manager manually, the problem disappears.
There is no problem when MSIE is open but only after it has been closed. Any ideas?