I bet you displayed the Windows task list and canceled OFP, thinking it was stuck. Well, here's another idea. When this happens, leave your computer alone for 2, 5, 10 minutes or more to see if OFP eventually succeeds to complete starting up. This happened to me on my children's home computer. Patience is a virtue.
One suggestion to resolving this specific problem that's worked for several people is to press your CD drive's eject button twice to eject and immediately reinsert the CD.
Another suggestion is to ALT+TAB out of OFP and then back in again.
If you don't like the long wait, take a look at this FAQ item and also follow the link there regarding your CD drive's ASPI layer. Just a hunch.