Learning how to program can seem like a daunting task. With a wide array of languages to choose from it is not so difficult to be overwhelmed before even starting. The good news is twofold: 1) as you learn one language it becomes easier to program in other languages and 2) you can get started learning by investing only a small amount of time and no money.
Often when students come to me or my colleagues for help with a programming problem they seem to think that they are one syntax error away from crashing the system. Well if you are learning to program you are going to make plenty of these errors. Back up your system (you should be doing that anyway) and then program away. While you probably understand this next point I still feel that I would be remiss if I did not say this: DO NOT learn to program on a production machine. What is a production machine? Any computer that is essential to your business.
What language should you start with? I would start with Windows PowerShell or Perl. Both are free and there is a ton of helpful pages about both of them on the Web.