Click by using MouseKeys

To click, press 5 on your numeric keypad.
To double-click, press the plus sign (+) on your numeric keypad.
To right-click, press the minus sign (-) on your numeric keypad, and then press 5 to click, or press the plus sign (+) to double-click.
To click as if you were using both mouse buttons at once, press the asterisk (*) on your numeric keypad, and then press 5 to click or the plus sign (+) to double-click.
To switch back to standard clicking, press slash (/) on your numeric keypad.

Notes

Make sure MouseKeys is turned on.
To change accessibility settings from Control Panel, click Start, point to Settings, click Control Panel, and then double-click Accessibility Options.
If MouseKeys doesn't function, press NUM LOCK, and then try MouseKeys again.
To specify whether NUM LOCK must be on or off for MouseKeys to function, on the Mouse tab, click Settings, and then for Use MouseKeys when NumLock is, click On or Off.
To change the pointer speed and acceleration when using MouseKeys, on the Mouse tab, click Settings, and then move the sliders to adjust the pointer speed and acceleration.
To temporarily increase or decrease the pointer speed, on the Mouse tab, click Settings, and then select the Hold down Ctrl to speed up and Shift to slow down check box.