SurferTim
Thank you for your reply. I wait for your link if it may help solve my problem.
When I open your second link, I saw a zoomkat's post in which I came to know that his sketch is the one I used and modified to suit my application.
Now I am happy to know the original sketch writer and might get help from him.
zoomkat, please help me if you can. Because I work based on your sketch. 
PaulS
Thanks for comments. But I noticed that after compiling, binary sketch size if 15006 bytes of 32256 max. Is it still not enough memory? Sorry I have limited knowledge of programming. I know only cut and paste, simple modification.
If it is memory problem, please give me more hint how to do. I also try to search how to improve memory because I need to add more function like Chennel Up/Down and DVD players function.
Thanks advance.