Windows Vista. some time ago we put in a usb webcam with a jack for built in microphone. I accidentally pulled the jack for the speakers and when i replaced the jack a box came up asking what we had plugged in i pressed side speakers and ok but the speakers would not work. We tried headphones in the front green jack and they worked so put the speakers jack in there too clicked the corresponding side speakers and clicked ok and they worked. The wouldn't work at the back. Yesterday I removed the speakers jack to put the headphones in and the same thing has now happened neither speakers or headphone worked. I have made sure all drivers are up to date, have checked all volume levels etc and plugs. Have turned computer off and on and with jacks in, prior to turning on.. The fact that it was all working one minute and not the next and that it's happened before, is really confusing any ideas?