I would try uninstalling the sound drivers in your device manager and then turning off the computer then back on. It should find the card and want to install the drivers. You could also try going to the card makers site and try to download new up to date drivers for it.
Thanks very much for all your advise. I eventually installed a new Sound Card. Working fine.
I think taking the old Sound Card so often I may have damaged it. The thin wire from the DVD to the sound card I tried to plug in and it was there that the damage was done. The tiny Black socket on the Sound Card where that wire goes moved out a bit.
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