No audio for MPEG's and streamed movies

So yeah, all of a sudden my macbook stop playin' the audio for all files other than MOV, WMV, and AVI. I tried downloading a few vids in MPEG format and they will play in quicktime, just no audio. I mean, YouTube and GoogleVideo won't even work, it's really annoying me. Any type of streamed video as well. I am not sure what it is, if it's a missing plugin or what.

I've deleted and reinstalled quicktime so that eliminates one option, anymore?

open /Applications/Utilities/Audio MIDI Setup and check the properties for Built In Output.

It might be set to 96KHz. Change it to 44KHz and audio and report back with the results.

Or if that doesn't help, trash the complete Macromedia Folder that lives in ~/Library/Preferences

BTW ~ is the shortcut symbol for Your Account.

Dunno what you mean by shortcut symbol and it's relevance to my account.

But i do know that your advice worked. It was set at 96 and i winded it down to 44, thanks man.

he was saying that "~" is the symbol that represents your user account or your home folder. so instead of:

/users/yourname/libaray/prefrences
he only has to tpe
~/library/prefrences

That also how it works in "Terminal" if you use it.