Depending on what sound card you have there are many options. You might try Start > Control Panel > Sound.
On the Playback tab select the current sound device and select Configure. Verify the configuration is correct.
On the Playback tab select the current sound device and select Properties. Then on the XXXXXX Properties dialog select the enhancements tab and see if there is a Pitch Shift setting or something simular available. Possibly disable all enhancements.
If the problem is still persists then try connecting some headphones to the headphone jack if available. If the problem is heard through the headphones also then this would be a device issue and you may want to update the device drivers to
your sound card and check device specific software, such as "Realtek Saound Manager" and visit the sound card's manufacture's support page.
Thanks, Jayson
