Inspiron 1545 and sleeping with lid closed

I have an Inspiron 1545 with Vista 64  that I got last year.  I recently got a LCD HDTV that allows me to be able to connect my laptop to it.  Not a problem connecting it (ok so it took me about 15 minutes to get the display resolution right) but a problem I never noticed before - my laptop is "sleeping" and shutting off the external monitor if the laptop lid is closed. I have the power options set for Do Nothing if the lid is closed and never turn off the monitor set as well. I can hear the music still playing and other things are still running on the laptop, however, the external TV is going blank with no signal and the USB connect sound goes off and back on once I reopen the lid.