Have you checked that your cd is a good copy? The md5sum should be posted along with the iso image you downloaded. Then compare that with the md5sum of your cd you burned. This is the place to start. If your cd is no good nothing else will help.
A newbie way to check md5sum is open K3b the CDRW writing package. Go to tools/cd/burn cd iso image. Choose cd image to burn. You should see a progress bar caculating the md5sum. When its done there is a little button lower right hand corner with a ...
Click on it and copy/paste Md5sum from website and compare.
johnb