I have a real problem with hooks

[snakekain]

Hi all,
i'm trying to monitor the system for hotkeys like powerstrip it monitors for hotkeys to increase or decrease gamma or whatever while any thing is active the first thing i thought about was hooks so i wrote my hook procedure in a dll setup the hook like this

///code in exe
gkbhookdll = LoadLibrary("kbhook.dll");//load dll
gkeyboardhook = SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)GetProcAddress(gkbhookdll,"KeyProc"),gkbhookdll,0);

i specified 0 for last parameter to be system wide every thing was ok

///code in dll
LRESULT CALLBACK KeyProc(int nCode,WPARAM wParam,LPARAM lParam)
{
MessageBox(NULL,"called hook","called hook",MB_OK);
return CallNextHookEx(0,nCode,wParam,lParam);
}

now strange problem is that when i activate another window then the hook doesn't work even if i reactivated my window, any one knows what's happening.
does CallNextHookEx returns something that Unhooks my hook?
Thanks for advance and if any one knows a better way for monitoring system for specific hotkeys please tell me, thanks every body again.
and if some body knows how to format parameters returned from the hook with CHotKeyCtrl.GetHotKey is welcome because of the parameter holding wModifiers.
The hook can only give you the code of one button and tell you if alt is pressed. Thanks for the third time.