After installing a new Power Color Radeon HD 3650 and the corresponding driver, I haven't been able to get any sound out of the onboard sound chip. Plugging in my speakers or headphones into the usual slot isn't working at all. When I check the audio devices through the volume control, it says that the HDMI output is the only available one.
I really don't know how to fix this problem, and I've gone as far as reinstalling the old audio drivers and completely uninstalling the ATI drivers. Alas, nothing has seemed to change.
I think the ATI card is overriding the onboard drivers. Clean out the drivers again, and only instal the Graphic driver for the Radeon, and not the whole package suite (which includes the ATI audio driver).