You might try here first,
Safari (Windows) Forums. This should help you quite a bit more.
This forum is more for trouble shooting how to install Windows on a Mac so unless someone happens by with your issue it may take a while here.
Let them know what OS your using, XP, Vista or Windows 7?
Let them know more information like,
you can no longer get sound out of Safari or the computer itself? Can you hear things normally when using any other application or even in IE?
Have you double checked the Sound control panel and see if it somehow got buggered up. You may just have to choose it again.
Try to explain more on what exactly happened and what you did to try to fix it.......