Set mouse or keyboard button to simulate left click and hold or rapid left click repeating in Windows?

you can create all your custom keyboard shortcuts using autohotkey. Autohotkey is a free open source software for macro and key binds.

http://www.autohotkey.com/

Here's the autohotkey script that will bind a keyboard shortcut (CTRL + g) to a mouse click.

^g::
click

Save this in notepad with the file extension .ahk then compile with autohotkeys. To compile autohotkeys scripts you will need to download it here:

http://www.autohotkey.com/

Also You can replace the key g with any letter to change the trigger key. To change from CTRL to ALT replace the ^ with !. For a complete list of symbols defining hotkeys see this documentation...

https://www.autohotkey.com/docs/Hotkeys.htm

MouseKeys is built into windows XP and higher.

Step 1 Turn on MouseKeys in Windows XP by pressing “Left-Alt, "Left-Shift" and "NumLock” simultaneously. Press “Enter” to select “Yes” in the dialog box that appears to activate MouseKeys.

Step 2 Move the mouse pointer left and right by pressing “4” and “6” on the numeric keypad. Press “8” and “2” to move the pointer up or down. The “1”, “3”, “7” and “9” keys move the mouse pointer diagonally.

Step 3 Simulate a left mouse click by pressing “5." Press “+” to double-click. Press “-“ and then “5” to right-click.

Step 4 Drag and drop by moving the mouse with the numeric keypad. Press “Insert” to simulate holding down the mouse button, and then press the “Delete” key to release.