Hi Raphael,

If you know how to do it in C/C++ using the Windows API, then you can
very easily do it in Ruby on Windows using the Win32API. There's a
getting started in the Pickaxe book
(http://whytheluckystiff.net/ruby/pickaxe/html/win32.html) - but this
is really just a primer. Once you've got your head around the
bindings, the real documentation is, of course, in the Windows API
itself, which is all available on msdn.com.
If you're not familiar with Windows programming in general, then, as
Axel said, you're better off using an easier GUI toolkit, which will
handle the Windows API stuff for you.

-- 
JJ