Use shortcut key to start gvim in Windows
From Vim Tips Wiki
created March 13, 2004 · complexity basic · author LunLun · version 6.0
I want to open gvim, in Windows XP, using a shortcut key.
To do this, I made a shortcut to gvim, and I assigned a shortcut key in the Properties menu.
However, I can start the first instance of gvim, but the same combination will not allow me to start the second instance; it will just display the first one.
My solution was to create a shortcut in the Start Menu. Now, I press and release the "Windows" key, and then press "g" once. It can launch an unlimited number of instances of Vim. Sometimes, I need to write a script in one instance and to see the output in another.
 See also
I used this shortcut target, under the "\Doc*Settings\All Users\Start Menu":
"C:\Program Files\gvim\vim62\gvim.exe" "c:/"
Vim opens the root dir of c:, from which I can navigate and open the desired file w/o a mouse and Win Explorer.
Where all else fails there is always autohotkey
Another way to use a shortcut key to execute more than one instance of gvim is to use Rundll32.exe and the ShellExec_RunDLL function. For example:
C:\WINDOWS\system32\rundll32.exe Shell32.dll,ShellExec_RunDLL "C:\Program Files\Vim\vim72\gvim.exe"