This has been driving me insane for several weeks. I turn the machine on, and (after a really long time of it launching lots of things) I get the I-have-successfully-launched sounds, and then immediately after that the sound completely stops working. When the machine is still launching stuff, if I right-click the speaker symbol on the right in the Toolbar, select Playback Devices, then right-click on Speakers (which is checkboxed as the Default Device, there is also Realtek Digital Output, and on Realtek Digital Output(Optical) below that), and select Test, sometimes it will take a few moments where, if I right-click Speakers again, it will show Stop Testing for awhile, and then suddenly I get the test tones, AND a flurry of other I-have-launched-this-thing type sounds, related to other programs that are launching at startup. But then it sounds like the sound effect is stopped a fraction of a second before its supposed to.... and from that moment onward, no more sounds will play. if I then right click Speakers and select Test, I immediately get a dialog box saying "Failed to play test tone." Other times, when I (re)boot the machine, and at that same moment in the startup, I do the above Test, and immediately get "Failed to play test tone." I can reboot and reboot and reboot and reboot, and SOMEtimes I'll finally get a session where the sound stays ON the entire time... but typically it takes me 2 to 3 HOURS of this repeated reboot song and dance. Much of this is because I have to wait 20 or 30 minutes before it gets to the point where it attempts to play that I-have-successfully-launched-these-things sound, while a large flurry of various programs launch form startup.... some of which behave as if they're held up waiting for the sound-player mechanism to launch... and then crash. This is really, really, really frustrating because I'm trying to get the machine up to speed for a scheduled event I HAVE TO be at that HAS TO HAVE sound working. Sometimes its a voice-chat meetiing, sometimes its a music event in a virtual world, or some other thing where I need to have sound working... and I've turned the machine on 2 or 3 hours in advance of it so everything is already ready already.... except that in te last few weeks I've had to keep rebooting the machine for that entire 1 oe 3 hours, watching the time being eaten away as that scheduled time rushes up closer and closer and then sometimes just goes WOOOSH!!!!! right on over my head as I'm STILL stuck in reboot Hell. I've looked at several other solutions where someone else had the same issue I have, where they said go in and run THIS thing from CMD in Admin mode that checks to see if any of the installed components of Win7 are corrupted.... and it found everything was fine. I've reinstalled the drivers, as acquired from the Realtek website. I've tried to follow someone else's set of instructions that involved drilling down into Registry to check to see if certain things in there are missing and reinsert them, only to find either that the possibly-missing Registry entry in fact IS there like it's supposed to be... OR that the subfolder in Registry that I'm supposed to go to isn't where that instruction tells me it should be. There was even one that boiled down to "Go disable this device, then re-enable it." It ain't working, and its making me scream at my machine. This has been going on for weeks. When it started out, it was only doing this no-sound lunacy occasionally, and usually a reboot sorted it the first try, but now it's doing this no-sound lunacy the vast majority of the time. This is on Win7 Ultimate, 64bit, service pack 1, on an AMD FX 8320 Eight Core Processor, with 32GB ram.