Likely there's some application running that is preventing it, but it is unlikely RR itself as most people (including myself) use some sort of shutdown controller that basically pushes the power button when you turn off the ignition (to initiate the shutdown). This could be a winamp plugin or even something messing with the power configuration. You may want to check the debug log as it would also indicate if there was any notification of shutdown attempts. It is also a known fact that in Vista/Win7 applications can not prevent the OS from shutting down or hibernating so I assume you're using windows XP - if this is the case I believe you can also modify some registry settings to not allow applications to prevent a shutdown attempt, but if it's something messing with the power configuration (i.e. to set the power button action to "none") then the only solution is to figure out what's doing it and remove/adjust it. If you want to verify RR doesn't 'block' the shutdown, you can simply run RR then while it's running click start->Shutdown and you'll see RR will not prevent it (There's no difference between that shutdown and the one initiated by windows when you press the power button).