livecds work fine
So when you boot from a cd you're OK but when you try to use a CD from within an installed Mint you're not?
These total lockups (if that's a word
) are a pain....
The reason is that your system uses all its resources when it tries to start the CD, but why this happens I don't know
Have the system monitor open when you try to open a CD - this may produce a lead to what's causing your problems