RIGHT click on the speaker icon in the lower right corner system tray, choose "Open Volume Mixer", then make sure the "System Sounds" is not muted by hovering over the little speaker at the bottom of the "System Sounds" column. If muted, click on the little speaker there.
Hope this helps.
Grif
I have checked the device manager, volume settings, etc. I cannot get any system sounds, at all, but have no problem getting internet sounds; youtube, facebook, yahoo etc. I am stumped. Can anyone help?

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