[Solved] No sound - Dell Dimension 2400

I just got Mepis working today on my 2 year old Dell Dimension 2400 - surfing the web nicely on Firefox, all running smoothly, but no sound. Where do I start looking to get this sorted? Please don't get too technical - I only started today I did find a mixer with all the sliders down at the bottom, so I slid them all up two thirds but still nothing.

BTW, movies like WMV play just fine. Just silently! (although one WMV said it didn't have the right codec).

Also, if I ever get the sound running, how do I play DVD movies on this box? Windows played them perfectly, so that suggests that the system is fast enough for great movie viewing. Probably be an issue with CSS/Regions/Macrovision and all that stuff.

Thanks,
Dominic

*****UPDATE****** I've got some sound now - YAY! I now have system sounds and CD Player sound. In KMix the headphone slider controls my volume - I clicked on the little round green "bulbs" everywhere (including Advanced at the bottom) to set them to glowing, and SOUND. Big sigh of relief....