Need to know if all the new dell laptop have microphone already installed

Hi, sorry if this is very vague, but few months ago my father and I purchased a new laptop for him. But I totally forgot what kind of dell it was but he moved out of the country and I have been trying to skype him. The video works but no sound, so I was wondering if the laptop have the microphone installed into it. And yes i have no idea what it is, but if I have to guess its an inspiron. If this helps, we bought it the day that window 7 came out. Any help is appreciated

Thank you.

Also, if the laptop do contain the microphone, how do you turn on the mike?