This is an issue that happens to me just sometimes, most of the times the emulator works ok.
screenshot of the problem with the emulator
The thing is, that the emulator starts but it can not be maximized. It doesn't matter if you click on its "window" from the Tasklist at the bottom or you try to force it to maximize/make it go to the front from the Task-manager; it just doesn't react to it. In the little window that appears when you have the mouse over the task (see screenshot), you can even watch the emulator starting and waiting for the interaction with the clock and so on, but it is not accessible.
Any ideas?!