Well, the format is in fact "CD audio"
I like to use Sony sound Forge Pro, it can convert just about any format into another. It's great for making CD files. Then I like to burn the file to disk with NERO.
Avoid (like the Plague) ANY free downloaded software. This type of software frequently contains spyware and viruses. Remember I warned you.
If you want to make a good CD, PAY for good software.
Thank you good advice (re free software) one was approved by CNet though so thought it would be okay. Will check out Forge Pro.