How do I get my "good" CD player/burner identified to iTunes?

Hi, I have an older PC laptop with an integral CD player that works for playing/importing but not for burning. I scavenged a BluRay unit from an even older non-functional laptop which I added externally (too fat to fit in place of the integral unit). But when I'm ready to burn, I can't select it. iTunes thinks the broken one needs a blank CD. I added a blank CD to it and was then able to select the other CD unit from the burn menu. But I couldn't even get to the burn steps where I could select the working unit without doing this. Is there a way to specify the CD unit to be used when there are more than one without having to do this dance?

Thanks - Dave