If you received the error message stating "no audio output device is enabled" or "no audio output device is installed," the problem could be simply that the device is temporarily disabled. There is a multitude of reasons that a device could have been disabled. The installation of an unrelated program could have caused the problem, or someone might have accidentally clicked something to disable it. To enable the audio output, there are a few places you can check.
Look on your Windows Taskbar, next to the system clock, for a small speaker icon. Right-click this icon and select "Playback devices." Look for "Speakers" under the "Playback" tab. If you do not see this, right-click the body of the window and click "Show disabled devices." This will add a check mark next to the text, which signifies disabled devices are being shown. Right-click the "Speakers" icon, or whatever audio output device you are using, and click "Enable." If "Speakers" is already present and has a green check next to it, Windows already has it enabled.
Open your audio playback software, such as Windows Media Player, and look for a mute button. Usually, there is a speaker icon with a slash through it, if the program is muted. Click the icon to enable sound.
Reboot your system and enter into BIOS or set-up. The method varies between computers, but try continuously pressing "Delete," "F1," "F2," "F8," "F10" or "Esc" while the system is booting up. You will eventually enter the set-up. Look for a tab which says "Hardware," "Devices" or "Enable/Disable." Locate your sound card, which may be integrated into the motherboard or installed as a separate card, and enable it. Do this by navigating with your arrow keys until it is highlighted, pressing "Enter" and selecting "Enable." Press "F10" to save and exit BIOS.