Computer won't recognize disk in CD rom drive

I am trying to copy some images that I have in a folder on my hard drive, but when I try to do this and it says to put a CD disk in the drive, which I do, but it still thinks that it is empty, and asks me to put a disk in the drive, which again, I do, and the same thing happens.
I am using Nero Express, but when I try to use the Windows XP default CD disk copy program the same thing happens - the disk is not recognized.
I used this program a week ago with success.
I do have a lot of stuff, mostly graphics, on my hard drive (this is why I am trying to put a lot of the images that I have on disks) because of the space problem, so maybe that could have something to do with it.
I have rebooted and the same thing happens.
Thanks for any help!

Go to Windows Explorer, right-click on the drive letter. Go to Properties, Hardware, Driver tab. Click Uninstall. Reboot your PC and Windows will automatically reinstall the burner’s driver.