HP XW4600 - Speaker icon has an "X" and says no speakers plugged in. The internal speaker is connected on the motherboard. Control panel "Sound" window shows High Definition Audio Device under playback but says not plugged in and doesn't show speaker icon in this box (as it shows on a similar HP box running Windows 7). Scanned for hardware changes but I can't enable the internal speaker! This used to work and the only thing I changed was a video card.
This is the larger internal speaker found on many HP desktops (not the beep speaker on the motherboard). You can actually use it in place of external speakers. It used to work before the video card went in. The options in the Sound window in the control panel are grayed out otherwise I'd try to add it. Scanning for hardware says "Troubleshooting couldn't identify the problem".