HI. Thanks once again for following up. The hardware test initially looked promising. I ran the Quick test on the system and it came up with Processor check - software error, everything else OK. I ran the Extensive test and it pretty well immediately came up with processor OK. Then I ran the Component test on Processor and System Board, both passing OK.
Strangely enough when I ran the Quick test again, the processor check came up OK :(
One thing that may be a clue: In the Sound panel in the Control Panel, I only see one device whereas most of the help screens (eg for updating drivers) show 2. If I click on that device (Microphone: Intel SST audio device (WDM)) and then go into properties and click on the listen tab it says "You can listen to a portable music player or other device though this mirophone JACK". Should I have another device for the internal mic? (Show Disbaled Devices and Show Disconnected devices are both ticked). Another piece of info: if I plug a mic (with a stereo jack) into either of the headphone/mic sockets I hear a buzz through the speakers as I m plugging it in (just like normal when you are plugging an input device into a live sound system). However, I do not get any signal coming from the mic. (Listen to this Device is ticked)
Hmmmmm. the plot thickens. Over to you, Sherlock!
Thanks
Max