Hi, when I purchased my pc the volume was set to mute. Nobody told me that I needed speakers to make it work. Call me dim if you like but I only had a work pc before. I tried various support sites for advice and one suggested uninstalling the audio output devices, so I did this and now have speakers installed, but still no audio (there is a red cross against the audio symbol in the corner of my screen and it states no audio output device is installed). How do I get them reinstalled?