Is your mouse it not working, then U can Use Your Key Board’s NumKey pad  as an alternative to your mouse. Here is how U can do itTo Activate mouse keys press Left Alt , Left Shift and Numlock Button.

Then, a window will be popped to u

After this Ur NumPad will start working as the Mouse.

U can use key 5 to select and other keys to move the cursor.

U can disable it by pressing the same keys again. But, remember, on activating it makes a notification but it does not make any notification on deactivating.