I suspect that your machine is infected with a trojan such as subseven (backdoor.g)
Ripper, November 2008
Hi, there are various rouge programs for controlling other peoples computers including opening and closing the CD rom drive. A virus check with a reputable virus scanner will help. AVAST free version would be a good start.
More info jazzy@jazzyjeph.co.uk
jazzyjeph, October 2008
Some CD/DVD Rom drive have firm ware which will shut itself after a set period of time. If it actually opening for no reason it may be an application that is asking for it to be open.