Sorry, I should have mentioned that I am using Windows XP sp2 32 bit. The option to send/not to send audio via hdmi is not available in Nvidia control panel change resolution page
But I have disabled Nvidia high def audio in Device manager and now it works.
Now there is another question. I have hooked both HDMI and DVI cables to the monitor. It automatically runs on HDMI but if I choose DVI cable as input source, monitor goes to Stand By. DVI doesn't work until I unplug HDMI cable. Why is this happening? How do I fix it now?
If someone wants to know why I want to use both cable , it might sound silly, but its very useful.
I like my monitor very dim while working on it or while surfing. But to watch a video, I have to do raise brightness and contrast and then back again.
HDMI and DVI they both use different video settings. So DVI for dim and HDMI for hight contrast and brightness. I step to make picture bright or dim.