VB.net 2003 **Hooks to get last application with focus

I have found a few posts by IDLE MIND and IMRAN.  Idle Mind had a good code which works with VB6. Unable to find now.  He used Shell scripts to complete.  

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Intercepting WM_ACTIVATE message for any window (detecting activation with hooks/subclassing)

https://www.experts-exchange.com/questions/21083100/Intercepting-WM-ACTIVATE-message-for-any-window-detecting-activation-with-hooks-subclassing.html

uMsgNotify = RegisterWindowMessage("SHELLHOOK")

    ' This basically registers our window to receive the shell events
Call RegisterShellHookWindow = (Me.Handle)
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UMsgNotify has an error that it expects a declaration
Call states Syntax error.

I have another open question just as this one.. Just looking for a solution.
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