I was just kidding.
I've read your other post about the troubles with burning.
Anyway, if during your attempts to write on those discs, a real attempt was made, a tiny bit of information could already been written to the discs, making them unusable.
Of course you can give it a try on another computer, using another brand of drive. But usually you can only use them as a coaster though.
If you're interested in a more or less technical description of things that are involved in burning CDs and DVDs, these KB articles may be of interest:
About default optical drive burning speeds
About optical disc drive burning and write speeds
Factors that affect writing to or reading from optical media
I love Mac and have used it for years but I have a really good friend trying to talk me into getting a PC because he says they do a lot of things Mac can't.
I usually don't go into these kind of yes/no 'games', but people in my vicinity sometimes tell me the same. My reply: "Name one".
Often they tell me you can't
get much software for the Mac (with 'get' they mean 'for free'). My reply: "I pay for my software".
Etc. etc.
Whatever you decide, have fun while using your computer, wether it's a Mac or a PC.
M