My laptop acer 4736z suddenly stopped playing DVDs.

Windows 10
Windows 10 uses troubleshooters to help you solve problems with your PC. To run a troubleshooter:
Select Start > Settings > Update & Security > Troubleshoot.
Select the type of troubleshooting you want to do, then select Run the troubleshooter.
Allow the troubleshooter to run and then answer any questions on the screen. If you see a message that no changes or updates were necessary, you can try recovery options, or find out more about Outlook error codes and upgrade and installation error codes.
Windows 8.1 and Windows 8
Select Start > Settings >Troubleshooting, and then follow the instructions for the kind of troubleshooting you want to do.
Windows 7
Select Start > Control Panel > Troubleshooting, and then follow the instructions for the kind of troubleshooting you want to do.

Have you tried playing CD's ... if the CD is playing properly and problem is only while playing DVD......then the lens of you DVD Rom is not working properly...you may need to give it for a repair.