Don't know if this is hardware issue, software issue or registry issue. (or none of the above).
Have an HP Compaq 6710b notebook (with regrets). This happened both in Vista 64-bit and happens in Windows 7 64-bit fresh load (on new hard drive).
The second turn computer on, "Mute" button LED lights, indicating speaker is muted. Yet, when system starts, it thinks soundcard/speaker are working. When I push "mute" LED on top of keyboard, the system thinks I've turned off speaker (have to manually click speaker icon on screen to "unmute", so it and LED on keyboard are in sync. Within about minute, LED on board automatically lights again, indicating muted.
I have tried numerous repair steps, including reflashing bios, fresh load of windows, replacing toggle board (with LEDs) as thought maybe that was defective. Have unloaded and reloaded drivers. Have tried using older versions of drivers, including 32- and 64-bit winxp, win Vista and Win 7. (oh, by the way, sound device is a soundmax HD audio, built in on computer board, which has intel chipset). Nothing HP has suggested works (they want me to take it in for service, but looking at hours I've put in, I'm more likely to be able to afford a small European country).
As mute button lights the second turn on power (and tried unmuting before windows loads, too), guessing maybe it's a registry issue, a startup issue, or because HP knows no solution [although I've seen others with same problem in forums - never seen solution] probably a hardware problem. I've already given up on HP, about to give up on the computer ever being usable for sound --don't want to have to push unmute button, then click on speaker icon to unmute, every minute or so.
I'm stumped. Does anyone have an idea how to fix? (don't have speakers attached, never did).
I am wondering if you have checked the default output settings under the Sound options in control panel. It seems that there may be another device which Windows has decided is the default or that there is another device in conflict with the speakers. It is also possible that the Sound Card believes that the only output it should be using is the auxilery output as opposed to the onboard speakers. The only thing I can think of after that is that the speakers are faulty and Windows is shutting them off to prevent their use.
I know you have probably resolved your issue a long time ago but for anyone with a similar problem, it turned out for me to be a silly user error. I just installed Win7 64 bit a couple of days ago and am not at all familiar with its quirks and tricks even still. All of a sudden out of nowhere this floating muted speaker icon starts drifting by. I looked at drivers, tried different inputs on the monitor quizzed and queried around and it finally hit me the following morning after I let my brain rest that it was nothing but the mute button on my monitor/tv had accidentally been engaged. I run all of my sound through a external surround setup and the monitor has an optical out. I NEVER use the volume on the tv for anything so I had never seen the icon before. LOL. I hope yours was as easily resolved! Sometimes you just have to laugh at yourself... The old forest for the trees parable stricks again!