Nothing happens when game CD is inserted

I was going to download a game onto my computer, and when i put the installation CD in - My computer doesn't say there's even a CD inside of my CD-ROM. I tried putting a music CD inside, and it's the same way. My CD-ROM is apparently fine, and "works" with my computer, but my computer doesn't realize there's a CD in there! Could someone please help me, or tell me what may be wrong?

PS: Could it be because my drive is CD-RW instead of CD-ROM?

You probably need a CD/DVD combo drive because the game is a DVD instead of a CD