You probably need some Windows application.
See this thread which talk about using C#. But the same API should work within LabVIEW.
Also have a look at the Windows API spying technique discussed here.
There is a C program that you may want to convert into LabVIEW which is found here.
There are more of such examples if you do a google search.
Unfortunately, there is nothing native to LabVIEW to do such a function (getting keystrokes from another application which has focus).
