If anyone needs to know: you have to reset your system defaults, which can be done simply by opening Garage Band. Odd but true! YOu can also do this via midi settings in Applications/Utilitites/Audio midi setup: set audio input to 44K Hz.
I have never said I was "desperate" in a post before ... but I am completely flummoxed with this one and can't do anything online that uses Flash sound - my Flash went silent on me. This is true on all browsers, including Firefox (my usual browser) and Safari. Video seems to work fine (I get normal picture on youtube, for example), the video portion of games works fine, but ALL Flash sound is dead, both in pure sound files (e.g., NPR) and sound that accompanies video/games. Pure sound files, such as streaming NPR files, buffer but then won't even pretend to play - the time cursor doesn't even move; it just sits at 0 as if no sound file is there, but it says it has buffered. iTunes works, speakers work. Have uninstalled Flash and reinstalled and rebooted (a half dozen times) - nothing. This happened soon after I had to use Real Player for something - could Real Player have done something to my Flash sound? Really appreciate any help or ideas!!