No sound after installing Radeon HD3650

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.

Any help would be greatly appreciated, thank you.