Every mobile device has its "PC Companion" software, whose purpose is repairing the smartphone's operating system, making backup of personal data, etc. For example, iPhones have iTunes, Sony mobile devices have Sony PC companion, etc.
Connect your device to the computer via a USB cable, (install and) run the software, follow the instructions by the software and wait for it to repair your device.
Note: Download the software from the manufacturer's website only to avoid getting your computer infected with a virus. Also, make sure that you make a backup of all your personal data, such as photos, videos, sounds and other documents before you start the repair process.
If you tried all the other solutions, but none of them worked, reset your device to its factory settings. Before you reset it, make sure to make a back-up of all your personal data, such as pictures, videos, sounds, etc., because they will be deleted from your device.
See the don't know how to reset my device guide on how to reset a device to its factory settings.
If you tried everything else to fix your device and it still doesn't vibrate, consider taking it to a repair shop.
If you can't resolve this issue by yourself, you can always contact your device's manufacturer's support team. They will instruct you on what to do in order to resolve the problem.
If you don’t receive the email in the next 2 minutes please check your junk folder, and add [email protected] to your safe sender list.