5.1 Receiver Good Value, But Be Forewarned How To Connect A Desktop Pc To A Dolby Digital 5.1 Surround Sound Audio Receiver?

How to connect a desktop pc to a dolby digital 5.1 surround sound audio receiver? - 5.1 receiver good value, but be forewarned

I have an HP Pavilion desktop and I can not connect to my Sony Dolby Digital 5.1 surround. How can I do that, to get full 5.1 surround-sound effect? Thank you in advance.