With multiple monitors apparent quota on number of changes

I've looked in this area of 7Forums plus I've Googled this issue but I'm not finding any relevant answers. Here's the problem I'm seeing. My motherboard has a built-in video adapter. (See my system specs for details.) There's 2 connectors for video output: a video port + an HDMI port. I've been running this system with an ordinary computer monitor connected via a video port to DVI adapter for over a year without problems. Recently, I was thinking I wonder if I can connect my HD television to the HDMI port on my motherboard. So I bought a 25' HDMI cable, snaked it around the baseboards on 2 walls of the room, and connected the HDMI port on my motherboard to one of the HDMI inputs on my surround receiver. The receiver has lots of inputs & lots of switching capabilities. The audio adapter built into the motherboad is & has been for over a year connected via an optical cable (another 25' snake job around the baseboards) to the surround receiver on its PC input. So this new HDMI cable adds a video signal to the already existing audio signal on the PC input of the receiver. It all works just lovely. I change my setup from "Show desktop only on 2" (my computer monitor) to "Extend these displays" back & forth on demand at will multiple times & it works like a charm.

Until . . .

After 2 or 3 days of doing this, I'll go to extend the display & I get an error message that W7 is "unable to save changes to display settings." All I can do is press OK & soldier on. What I have found is, of course, the usual cure to anything that ever goes wrong with Windows, that after a reboot, everything is fine again & I can use just the one or both monitors, switching back & forth, just fine . . . until it's not fine again!

Does anybody know why this error occurs? It's as if I have a quota on how many times I can change my display settings before Windows throws up its hands & tells me it can't take it any more. Is there some way to make it change the settings without rebooting? One solution I saw offered in my Google search was to do something in the Registry & then redetect the 2 monitors. Problem is that advice was tailored for a situation where a laptop user wanted to use his nice monitor when he was at home instead of using his laptop on his lap at Starbuck's or something. I'm not afraid of messing with the Registry but this sounds like an awfully extreme thing to have to do. I believe I wouldn't have the particular Registry key mentioned in that advice anyway since mine is NOT a laptop system; it's a desktop.

All ideas gratefully accepted.

I thought perhaps I needed to do things in a specific order. So I've been making sure the surround receiver is on & the PC input is selected before I change my display from "2 only" to "extended." Doesn't matter. I've just had to reboot yet again anyway. See the problem is, as soon as I turn the surround receiver off, Windows thinks I've detached the second monitor. This has the unwanted side effect of shutting off the audio adapter output. In order to wake Windows up & start sending audio out once again, I have to make a change to the monitors. A change. Any change will do. "2 only" to "duplicated" and back again, for example. The TV doesn't even have to be on, just the receiver. This does successfully wake up the audio support . . . until I reach my apparent quota again & I have to reboot just to listen to Spotify. I sure do wish somebody with some knowledge in this area would respond here.