DVD/CD writer has gone awol

I have a Pioneer BDR-205 dvd/cd writer and it has worked fine for a year opr so. Howver, yesterday when I tried to make an audio cd the writing came to end prematurely with an error message. Also, the writer seems to have a lot of trouble seeing blank disks - it has told me both that the (blank) disk is full, or that there is no cd in the writer. I have upgraded the writer's firmware but that has made no difference. I have bought a replacement writer which arrives tomorrow but I'd just like to get some idea of what may have been going wrong.

Thanks for any ideas.