.... my CD is very dirty and scratched ...
Try taking it to your local DVD rental store and ask them if they could run it over their polisher / scratch remover. If disk has light scratches, should come out looking like new. If disk has deep scratches, information has been lost and will not be a reliably disk.
Not safe posting your email address in public forums. Leads to massive spamming. Questions brought to a forum are to be answered in the forum. This way people with similar problems came find the solution.