ATI Radeon HD 5450 card is the video card installed in my PC. Everything was fine until I upgraded to windows 8. I have a Dell 27" Monitor which is connected to the card with HDMI. Now, I dont getany sound and it has been a mute experience with Windows 8. Of course, I have updated the drivers, AMD high definition. Tried the front and rear ports but the result is the same. Help!