I'll try to be as DESCRIPTIVE AS POSSIBLE. It simply says "No speakers or headphones are plugged in." My speakers cable is secured at the back of my PC, but it's telling me that it isn't. This started to happen AFTER I tried to update my drivers. The whole reason I'm really wanting to update my drivers anyways is because they are saying they are designed for Vista and not Win 7 (the funny things is it only just started saying this not too long ago and I haven't done anything), and so I can enable/disable stereo mix, etc. I've googled for 3 hours straight on this problem and it seems to be a very common problem amongst people using Realtek audio. My sound isn't disabled in the BIOS, it isn't disabled in device manager, I've tried installing older and the newest drivers, none of it works. It's starting to seem that there is no solution to this. Try googling "No speakers or headphones are plugged in." and you'll see what I mean if you don't understand me.
It would probably help to say what the driver version is for the one that works, it's driver version 126.96.36.19956, I'm also on Win 7 64bit, and my motherboard is a Biostar P43D2-A7 (shitty motherboard btw, I totally regret buying it)
simple answer.. if one driver works and another driver doesnt.. there is a problem with the drivers.
maybe the output jack is triggering the 'no speakers or headphones are plugged in' error.
the way those work has to be implemented into software.
when the connection is made, the circuit changes resistance.
although it seems to be more work that quickly necessary..
if the software says the resitance needed to consider a complete or open circuit is different than what the connection is doing.. then it would be a valid culprit.
chances are, the circuit that 'senses' when the speakers or headphones are plugged in is probably weak/bad.