I do not hear any sound from my computer

I recently bought a second hand desktop from a friend of mine with a Dual Core processor. The sounds program is Realtek 97. I noticed that there is no sound coming out from the computer. I tried accessing the speaker volume at the lower right hand of the monitor.
I tried to check if the speaker is on mute. When I adjusted it, there is still no sound coming out from the computer. I tried the help menu and it pointed me to the control panel – device manager system. I followed the instructions in the device manager.
