Here are some things to check on...
Check your graphics driver version and make sure you are using the 64-bit version from this page:
Try different HDMI cables, if you can; be sure they are HDMI 1.4 cables.
If you are uisng any display adapter/dongle, try without.
Check the steps listed in the Multiple Display FAQ at http://www.intel.com/support/graphics/sb/CS-031040.htm.
Check the troubleshooting steps listed on the HDMI FAQ at http://www.intel.com/support/graphics/sb/CS-034397.htm.
If you still have the issue, then, with monitor and TV connected, please get the graphics driver report - instructions at http://www.intel.com/support/graphics/sb/cs-009476.htm