.Net Reflector is a program for de-compiling non-obfuscated or cleaned .net programs. Here il has been selected as the output language. Other output choices are C#, Visual Basic, Mangaged C++, and F++. There are a few useful plugins for Reflector. With the Reflexil plugin loaded. It is very easy to apply patches with reflexil. By right clicking in the Reflexil panel (lower right) it is possible to edit the highlighted instruction or create a new instruction. For example, can change br.true.s to br.false.s by typing directly in the entry box or using the pull down box suggestions. Save changes by right clicking the exe in the explorer pane (on the left), select reflexil->save as. To work with the patched file close the current project and open the patched one. Reflector trial version http://www.red-gate.com/products/dotnet-development/reflector/ Reflector plugins http://reflectoraddins.codeplex.com/ Edit: these low quality screenshots look crappy displayed small size in the popup viewer; to read the text clearly, right click and load in new tab.