Your CD drive may be very slow. But an hour and 30 minutes? That's a bit too long. It is safe to restart the computer.
Go under your BIOS and for boot order, set the CD drive to the first boot device.
Also, just give it another shot and try booting it to the CD.
The disk may be scratched and need cleaning
Various ways to clean a CD
I personally have never really had to clean a CD so I can't attest to these methods, but they are logically sound methods, in my opinion.