I think I can find out, if you need the BIOS password.
Is the sound driver loaded? To find out, open a konsole, and run the command '/sbin/lsmod | grep snd' run the command without the quotes.
If it is loaded, you should see several lines reported. Copy and paste the output here.
Have you opened a mixer to verify sound is not muted? or volume turned up? Some distros mute it when first installed.
I went to the Lenovo site. To get any information on the BIOS, I need the machine type and model. It is on the sticker on the bottom The machine type is a 4 digit field like 2624 or 2626. The model is a 3 digit field, there are way too many to list here.
Here is the link.
If you post the information, then we can find more information on the hardware.