Why is there a blu-ray drive showing up in my computer?

When I open My Computer in Windows 7, under the Devices With Removable Storage category, it lists a blu-ray drive. WHY? I don't have one! (I know because I built my pc myself.) I just have a standard DVD/CD read/writer and only one HDD. when I double-click on it it just tells me to insert a disk into BD-ROM Drive (F:). Why is it doing this? Very odd...