I have aspire 7745 laptop running windows 7 premium 64bit. I had the video & sound working on the TV via the HDMI cable but it stoped working. Now the TV "sees" the HDMI signal (and receives a low tone) & the computer "sees" the TV as a secondary display in the device manager. but no signal or sound. i have tried many ideas found here and other places on line but no change. Please help.
Laptops quite often require that the TV be connected (tuned to proper HDMI port) and turned on prior to booting the laptop. Some laptops have the ability through function keys to change display settings (usually blue writing on the keyboard).