cd-rw burning question

I was trying to erase a couple of these disks in XP. I get the message
if I want to erase and I say yes. It goes through its thing and as the
ribbon which is green comes to the end in seconds, it stays that way
while below it is a message that it should be completed in 5 seconds. I
wait and wait, how about a couple of minutes and it stays that way. I
try to cancel and I'm told that if I cancel, I more than likely would
make the disk useless. Well this happened to 2 different disks and
decided to get rid of the disks. During this process, I can't eject
even if I cancel, so i have to reboot to get the disk's removed. Just
curious, are those disks kaput? Anyone know why this would happen? I'm
thinking of the future disks. They were Memorex disks.