First my cd drive read cds but suddenly it started to give me an error function saying "incorrect format". I taught it was the blank cd but I tried others and it work. Now, it does not read any music cd and blank cds.what could be a cause for this.

Have you tried all types of discs, dvd, data, music, etc...

Any changes that either happened or that you perhaps made to your computer around the time that the problem started; particularly any Software or Hardware that you installed or setup.