DVD

Hi, I'm having trouble with my DVD/CD player, it seems that it wont play
neither DVD's nor CD's continuously, it skips micro seconds, like the machine
was slow or it would be reading it at a slower velocity, after it reads a
chapter of a DVD movie, if a play it back without restarting the computer it
will play continuously. I just bought the computer, a month a go, so it
should'nt be having this trouble.
If any one would have any suggestions about, what might be going wrong!
Thanxs