Help!

Last night, in order to clear some space on my hard drive, I transfered more than 400Mb of memory to a rewritable CD (one I had used a couple of times before, which might be significant). This morning, having resolved the problem that asked for space to be cleared, I thought I would take the memory from the CD back to the hard drive. Only, my computer absolutely refused to read the CD. It knows it is a CD, it knows that it has a lot of stuff on it - since the data refer to 277Mb free space - and it knows its name, but it does not recognize any of the hundreds of files on the CD at all. Since the items involved nclude dozens of songs, pieces of classical music, e-books, and so on, I am not disposed to just write them off.

Can anyone suggest something I could do to open this CD, or a community or website or blog where I could go for reliable advice? (Don't suggest Microsoft, they're useless.)

Thank you.