For some reason, if you interrupt the simulator while it is being loaded through "Run As" (not tested in "Debug As") by right-click > close. It will fail to ever start again. Even after IDE/PC restart.
I assume it's a bug, which is only solved by reinstalling SDK :S
If you forgot to do something, better wait till the simulator has loaded your app (or, at least, the "desktop"??) and then close it.
Happend twice to me already...
