How can I download turbotax installation media to my PC. I bought a CD at Costco but I have no CD drive on my computer.

You will need to contact our customer service department so that they can issue a download version to your account.

https://support.turbotax.intuit.com/contact/

would like to download turbotax ...i bought from costco

Please see this TurboTax Help article for instructions:  I bought the CD, but my computer doesn't have a CD drive