A lot of you are burning Data files instead of plain .cda files.
Data files will not play in an ordinary disk player unless it has the option to play mp3's.
An ordinary .cda disk can only contain 10-12 pieces of music like a CD you buy at the shops. A data CD can contain up to 300-400 mp3's. You must make that distinction when you are starting to burn a CD. you must either burn a data CD which will contain mp3's or you can burn an ordinary Audio CD (usually all the files will have the extension .cda) and it will (or should play) in your home or car CD player.
There is a big difference in the two types of files you can burn.
You have to select either data or music CD when you begin the burning process.
I know most of you know this already but others are less clear on what they are doing.
I hope this makes things a bit clearer for at least some of you.