I have a Asus EN9600gt graphic card with only 2 DVI ports. I use a DVI to HDMI adapter to connect my PC to my TV with a HDMI cable, and it does not work. I have test the adapter on my HDMI monitor, it is ok. My brother have a laptop (Nvidia 260M) with HDMI port, he can connect to my TV without any problem (the same HDMI cable). I have updated the display driver to the lastest from Nvidia. I am wondering why I cannot connect to my TV, everything just works fine.
This may be an obvious question but have you gone into the Nvidia control panal and gone to set up multiple displays and activated the tv in the menu? My laptop will automatically send signal to TV but desktop has to be configured manually