My computer dont want to play a dvd movie. my computer use to play dvd movies but know it dont want to play. please help me

Did you play the same DVD or the different one? If you play the same one, clean your DVD before putting into the DVD drive. DVD disc drive lens cannot read discs properly if they are dirty or dusty. To ensure your DVD plays correctly, clean it with a soft cloth first.
If not, Check your DVD region codes. Here is the detailed guide about how to Play DVD in Windows. Hope it helps.

With a free DVD player program, you could freely play DVD disc on PC. Leawo Free Blu-ray Player is the prior free DVD player software for you to play DVD on Windows 8/7/8.1/10 for free. This DVD player software freeware offers lifelong free service for playing DVD discs, DVD folders, DVD ISO files and IFO files on Windows. It is also a region free DVD player software program that could play back all DVD discs from different places and countries.

Thanks

Dvd movies required codecs according to different format so try to download divx codec which is very good and commonly used from www.divx.com and its free or click here http://www.divx.com/divx/windows/download/index.php
run it and enjoy