There are not many situations where you may need to substitute the mouse with the keyboard. Maybe your mouse just broke down and you need to finish a job before you can get a new one, or your notebook's touchpad is broken and you do not have a mouse in reach, or the battery of your wireless mouse just did and needs to recharge.
Whatever the reason, if you require a mouse but do not have one, you can use the keyboard instead.
The Windows operating system comes with options to use the keyboard for that, but it is not enabled by default. You can enable it temporarily with the keyboard shortcut Alt-leftShift-Num Lock or permanently in the control panel.
To do so, type "ease of access" on the search or run box of your system and select the result that opens up.
The "Make the mouse easier to use" menu is what you want to open. Here you need to enable the "turn on mouse keys" feature. Basically, it enables you to use the numpad keys as a mouse substitute.
Once enabled, use the 1-4 and 6-9 keys to move the mouse pointer in the selected direction, the keys / to left-click, * to middle click, and - to right click.
Additional information about Mouse Keys are available on the Microsoft website.
You can alternatively use a third party software such as Neat Mouse to simulate the mouse using the keyboard. The advantage here is that it provides better emulation thanks to additional options that it makes available.
The program is fully portable, which means that you can run it from any location after the initial setup. The movement keys remain the same by default, but you have now options to remap them if you like. This is especially useful to users who do not have access to a Numpad.
Left, right, and middle mouse button have been mapped to the 0, Enter and 5 keys, but they too can be remapped if so desired.
In addition to those keys, Neat Mouse makes available keys to scroll up or down using the / or * keys on the Numpad.
To activate mouse emulation, hit the scroll lock button on the keyboard. This button, as well as the scroll keys can be remapped as well.
Neat Mouse offers several additional features of interest. You can alter the speed of the mouse pointer in the interface for example, which can be useful depending on the screen size of the monitor. You can define an alternate speed and use a modifier key, Left-Control by default, to use it instead of the regular speed preference. Helpful if you need refined mouse pointer movements for some applications.
Profiles are supported by the program, which means that you can create different keyboard profiles for mouse emulation, for instance based on different devices that you use, or different purposes.