Today I noticed that a "BD-ROM Drive" appears in My Computer.

I do not remember installing anything that would've done that.
What could've caused this?
Today I noticed that a "BD-ROM Drive" appears in My Computer.

I do not remember installing anything that would've done that.
What could've caused this?
The likely explanation would be that you installed virtual drive emulation software such as Daemon Tools, Alcohol 52%/120%, or PowerISO (or another disc-burning software that has drive-emulation capability).
In most cases depending on the version and program used, a virtual drive is added automatically after install.
In Daemon Tools you can also click on "Remove all drives" and this will get rid of all the unwanted BD-ROM drives
BD-ROM DRIVE means Blu-Ray Disk Read Only Memory Drive.
It usually appears when you install a Virtual Drive using softwares like Daemon Tools, PowerISO, etc, and it is used to mount .ISO files and many other data formats.
I used DAEMON Tools, as mentioned in other posts, and a lot of BD-ROM drives appeared on my computer; actually, they took over all the drive letters, from E: to Z:. On my laptop, I couldn't use any USB drives. With no drive letters remaining, when I insert a flash USB, it can't mount on Win8.
I went to disk manager under device manager and disabled several of them. After that, USB was able to mount.
The OP has only one BD-ROM, so that was not the problem in this case. But this may be helpful to someone else.