CD/RW doesn't recognize CD inserted.

I have a newly installed Memorex 52X CD/RW with Nero 5.5 software. I tried updating a cd-rw disc using their multisession system, but I got error messages. So I decided to just burn a new CD. But now I keep getting a message to insert a media and I do and the CD/RW drive light blinks but it doesn't recognize that a cd has been inserted. It does the same if I just try to read a Cd. I'm perplexed at why it just stopped working. Does anyone have any idea.

 

Can you read a cd in dos mode? Boot to a dos prompt using a boot disk with cdrom support and see if you can get a directory on a good, known, working cd.