Why the cd are working propely in cd/dvd drives but not working dvd? What was the problem?

Did this just start happening or did you just notice?

Have you tried more than 1 dvd? One that you know worked before?

It can play music cd's?

In windows explorer and you have a dvd disc in, does it show in windows explorer?

If you have dvd in drive, what happens if you right click on drive in windows explorer?

Are there any errors in device mgr?

Start, settings, control panel, system icon, hardware tab, click device mgr - Any Yellow marks anywhere?

Try to provide as much info as you can as far as, what you notice, what you have tried, any messages come up anywhere?

More info will always help and hopefully not require to ask so many questions.