Question Author
Thanks for your advice - to answer "Closer", I only have one CD drive & I know where I put the CD. I was just hoping that there might be a quick & easy way of getting the CD out again without having to dissect the whole base unit, but I suspect that isn't the case, so it'll probably have to be referred to a technical expert.
To answer bish_bish - it is my work computer, so I can't take it to a shop & we don't have any technical people on site, but I'll call in re-inforcements.