olivjh,
There's a chance the Sound Preferences were changed on the new install... start at the Apple logo in the main menu.... Apple logo-->System Preferences-->Sound (second row, last icon)-->Output tab.
Since there is sound from the internal speaker select a different output setting...
I did not work for me.I did the combo update, and after rebooting all i get is a apple logo and then a black screen, any suggestions?