Soon I will be coding the file patcher for my application (check if the files are up-to-date and download newest if not) so its not much to code.
The problem is that I don't want the application users to be forced to use additional libraries like .NET (even though I like to code in vb.net or C#). I keep in mind that the .NET framework is installing together with the Windows but still there are plenty people who somehow doesn't have this framework installed, and thats why I'm looking for the programming language that wont require an additional libraries to run the application.
I haven't got much knowledge about programming in C++/Java but I have some experience with the AutoIT, vb.net, C#.
So the question is, what programming language will be the best for this purpose?
This answer is for "what language is available on any version of Windows without additional requirements". There are many other options for "what I can use to create application that can be xcopy deployed on any version of Windows".
JavaScript is probably your best bet - it is supported on most recent versions of Windows (according to Wikipedia article - Windows Script Host JavaScript available for scripting starting with Windows 98). Allows basic operation with files and HTTP communication - maybe enough for simple patching application.
Next would be native Win32 application, but lack of C++ experience will make it hard.