Oddly enough the other desktop is just fine.
Hmm, It sounds like there may be incorrect BIOS Settings. Some PC's have audio set up in the BIOS. I would check that to ensure the correct settings are selected for the audio device if possible.Soubd card isn't the issue as for the last week I've used a known good USB sound card and same issue.
Seems to me like all the other hardware is working just fine as well.
It's too predictable to be a hardware issue in my opinion.
I've currently left the PC up and I can go now and restart and I'd have the issue. I can then restart again and the issue is gone.
The sound card is a pro audio sound card and has outputs on the rear and inputs on the front.
The other PCI sound card I did use (unplugged it) had a plug in cable for inputs and outputs and everything was clearly labeled.
I can check BIOS but I don't think it has anything for audio settings.
Unless a Windows update changed the BIOS (if that's even possible) then it shouldn't be a setting.
However could it be another setting that doesn't play well with an update?
And if so with BIOS set the exact same on both PCs wouldn't it affect them both?
The only differences between the two PCs is the processor and a video card and the power supply.
One uses a faster processor, a PCI-E video card and a 500 watt power supply and the other that works fine doesn't, uses the stock power supply and uses motherboard video. I don't have the processor names handy but I can get them when I get home.
However those were installed before the issue happened.
Also the PC with the better processor and video card has the processor overclocked and video card overclocked and I want to say the issue was there either before I tried overclocking or happened some point after overclocking. I However did disable overclocking and still had the same issue.