Do you have headphones you can try? If external speakers don't produce sound, though, headphones probably wouldn't either.
Click the Volume Control speaker icon, then click Mixer (or right click and select Open Volume Mixer) and make sure nothing is muted.
Check the configuration of your speakers in Windows.
- Right click the Volume Control speaker icon in the taskbar and select 'Playback devices'
- In the Playback tab, right click the 'Default Device' (with a green checkmark) and select 'Configure Speakers'
- Make sure the 'Audio channels' configuration matches your speaker/headphone setup; press the 'Test' button to hear sound effects played on each speaker, while the corresponding speaker in the 'Speaker Setup' window is highlighted. You can also click directly on the speakers in the picture to hear the test sound effect on that speaker only.
Try changing Windows sound quality (right click the volume control in the task bar, select Playback devices, then right click on the default device [such as 'Speakers'] and select Properties, and in the Advanced tab, lower the quality [ie if it is on 24 bit 48kHz studio quality, maybe try 16 bit 48kHz DVD quality or 16 bit 44.1kHz CD quality]).
Try checking for updated sound drivers, or uninstall them and reboot to re-install.
Try doing a clean boot and check if you get sound after Windows loads (or during, if you have a startup sound set). Click Start, or hit WinKey-R, type in msconfig and hit enter; in the General tab, click Selective Startup, uncheck Load startup items (if required) and leave Load system services and Use original boot configuration options checked. Next, click on the Services tab, check the box to Hide all Microsoft services, then click the Disable All button (maybe make a note of which are currently enabled/disabled), then click OK and reboot the computer.
Run msconfig again to switch back to the normal boot configuration.
