No doubt that a number of keyboard shortcuts pave their way in, however, they may not be useful all the time, and are certainly not as efficient and durable as the mouse. Moreover there are a lot of functions, which cannot be done using the keyboard.
List of Factors
It is the most common problem. The device may stop working if there is a loose connection. If it is so, detach the cord and plug it in again. If you are using a PS/2, then you might require to restart your computer after unplugging and plugging the cord. This problem might also arise if the wire is twisted, bent, or damaged in any way.
The device might have gathered dust and dirt, due to which it may not function well. For this, remove its base, take the ball out, and clean all the dust and debris entirely. If your device is optical, clean the optical eye at the base.
Since it is a hardware device, it can stop functioning if the device drivers are not set. For this, you need to restore the system or reinstall the drivers.
Sometimes, the problems may be minor, such as the double-click not working, or the device is too slow. In this case, the settings need to be changed. For this, you need to go to the Control Panel, and select the Mouse option. In the dialog box named Mouse Properties, you can change the settings, and your device will start working properly.
The device may stop working because of some problems with the serial port. The problem may also arise after you get your system upgraded. One reason behind this may be that the old cable, which was attached from the serial port connectors to the motherboard headers are left in place.
A virus attack is a very common reason for the malfunctioning of this device. If this is so, you need to run your antivirus program and clear the system of all the viruses.
A PS/2 style uses what is known as IRQ12. In some cases, it has been found that this creates a resource conflict, i.e., when two different devices are trying to use a system resource like an interrupt request line, DMA channel, or an I/O address with another device. Using a PS/2 on a serial port also makes the device useless.
Change the Device
If all the above troubleshooting tips do not work, I am afraid it is time for a replacement. The device is probably completely spoiled beyond repair. Try to use a different device and see if it works.
Hopefully, you now have an idea of what to do if your mouse stops working. Use this tips effectively, or call in a hardware expert to diagnose any serious malfunction.