Sound from cd and sound from a site has nothing to do with one another
usually. But try that first....

Then go to System-Preferences-Sound and see if the box next to "enable
software sound mixing" is crossed. If it is take the cross away. That
might work.

And if it does not you could try this:
sudo ln -s /usr/lib/libesd.so.0 /usr/lib/libesd.so.1
sudo mkdir -p /tmp/.esd/
sudo touch /tmp/.esd/socket

Now my sounds works and I had the same problem. Thing is that when I
tried those three commands last night it worked fine after. Then today
after starting the computer up again it didn't and then I un-crossed
that box and it works. However, I haven't re-started since so i may have
to do it all tomorrow....only take a few seconds though.