Look for three walkman-type minijack sockets on the computer body (or read the manual regarding audio input/ouput?) they will be line in, line out, microphone.
I was only provided with a quick guide booklet - there is no reference to audio input/output in it. I only have 2 jack sockets on my laptop
It was a repalcement provided my my insurance company last year due to mishap with my original laptop - I get the impression they've palmed me off with a cheap substitute