Windows 8: Radeon 5770 HDMI output stopped working

Hi,

today I came home and HDMI output does not work anymore. I did not change anything. Now I tried upgrading ATI drivers and it still does not work. What could be the problem?

I have Windows 8 and ATi 5770.

Thank you for any tips.

I tried HDMI connection with different computer and every think was working. Soo there must be problem with my computer. But what?