Let's get the most obvious out of the way first:
1.) Is there already any data on the disk? If so, was the disk "finalized" when you last wrote to it? If a disk was finalized, you won't be able to write anymore information to it.
2.) Are you using a compatible disk? I had this problem once and it turned out that I was using an incompatible disk type (my drive won't write to DVD-R)
Also, make sure your cables are still tightly plugged in. Sometimes cables and components can come loose. But the fact that it recognizes that you do have a drive E kind of tells me that everything is fine, but you should still check anyway (I always open up my computer every 6 months to clean it and check for loose components and loose cables).