What have I done to my keyboard?

I was trying to figure out how to set up keyboard macros but it was just too complicated for me. I downloaded Keyboard Maestro and couldn't make much sense of it either.
However, in the process I have somehow done something to my system which is now keeping me from typing the capital letter "t" and when I try to type the capital letter "d" a document pops up and all of the text is highlighted but I can't type the capital letter "d" anywhere.
wth did I do? And more importantly, how do I fix it?

 

Thank you very much. I've got my T and my D back! You are a lifesaver.