DVD Drive keeps opening by itself

Hi

Since I purchased my Dell computer in December the disc drive keeps opening by itself regardless of whether or not there is a CD in it. As soon as I switch on the computer it opens and reopens every time I close it. I have checked the properties which states that it is working correctly and a diagnostics check stated that all software is fine. Has anyone else experienced this problem? As I said this has been happening since I first purchased the computer and has become more frequent to the point that it no longer stays closed unless the computer is off.

Any help would be greatly appreciated