alternatively, if this doesn't work you could press alt+f4 and this will enable microsoft's automatic double key-pressing feature. much like sticky keys.
I refuse to allow this forum to be filled with alt-f4 sarcasm and i will remove anymore of this nonsense, you may post your random crud in the insanity section where nothing really matters anyway. the person had a legitimate question and all this does is make people think that the actual "real" people on this forum are a bunch of "unleet super-noobs" or whatever those illiterate script kiddies call language now in this modern day.
Back to the original topic.
You are looking for a way to double press a key, equivalent to pressing Left mouse button twice for double firing of weapons. As bellend mentioned there is a very user friendly scripting program called AHK (Auto Hot Key). There are many tutorials found around the internet, you may find better support with what your exactly trying to do on their forums, but you are more than welcome to post any questions you may have here.
-Sym