I inserted a disc for school, computer concepts, and it was running fine but then it said not responding and crashed. I restarted my computer and re-inserted it and now it won't come up at all. I've went into My Computer and tried to run it manually and it doesn't even recognize a disc in the drive. I've checked for updates and it says I'm current. I also inserted another disc and it won't come up either. What do I do? (I have a Windows Vista if that helps)

No, it didn't help. What else can I do?