Recently I've come across the problem of having no audio on my HP Pavilion dv9700 Notebook PC, it simply tells me that 'No Audio Output device is installed'. I upgraded my computer from Vista to 7 and for 5 months had no problems. I've tried to install things such a Realtek and also tried to Scan for Hardware Changes and Update driver software, but nothing has worked. Also, in my device manager, under Other Devices there are 3 yellow signs with exclamation marks in front of 'Coprocessor' and also in front of two 'pcouffin' devices, I have no idea whether these are the roots of the problem or not. Is there any way that I can fix this problem?