Some DVDs not being recognised

Hi,

On a HP Pavillion laptop using Vista when I put a dvd in they are sometime not recognised. It's strange as other dvds play perfectly and there doesn't seem to be anything differentiating what will play and what won't.

I've made sure the drivers are up to date and have uninstalled and re-installed the drive but the problem remains.

Any ideas as to why this is happening or what I can do to solve it?

Thanks

Jd

 

Movies - I've not tried a data dvd