Alienware PC: Cannot install games using DVD RW drive

Hi: I've never been able to install games using the DVD RW drive that came with my: Windows 7, Alienware_X51_R2 Desktop. This wouldn't normally be a problem since I download all my games from Steam, but I have a game that isn't available online; and have other games that I don't want to repurchase...

The games will work on every other computer in our house (3 PCs), but not the Alienware PC; and I don't use those PCs often anymore. the CDs are in perfect condition too.

I ran the diagnostic tests and everything passed.

EDIT:

I can see and open files in the disc.

DVDRW will play DVDs, never had an opportunity to use a CD.

I tried playing C&C RA3 and that was a DVD-ROM, but it wouldn't install either.

I'm tech-savvy by way of being a Millennial, so aside from obvious fixes or replacements, I don't have specific technical knowledge.